Key Points
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Miscarriage and ectopic pregnancy are the commonest early pregnancy complications.
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The diagnosis of early pregnancy failure should be made on transvaginal ultrasound scan given its high diagnostic sensitivity and specificity.
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Sporadic chromosomal abnormalities are the overriding cause of miscarriage.
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Early pregnancy failure should be managed in a dedicated early pregnancy unit.
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Management of early pregnancy failure can be expectant, medical or surgical depending on the clinical situation and patient preference.
Miscarriage
Miscarriage is the most frequent complication in pregnancy. It has been reported that 12% to 24% of women who have missed a menstrual period and had a positive pregnancy test result experience the loss of a pregnancy. The rate of miscarriage reduces as the gestational age increases. Three percent of women having a routine first trimester ultrasound between 10 and 13 weeks are diagnosed with a delayed miscarriage, and the incidence of a second trimester miscarriage has been reported as between 1% to 4%. Approximately 25% to 50% of women experience at least one miscarriage during their reproductive years. An estimated 125,000 miscarriages occur every year in the United Kingdom, and these account for more than 50,000 admissions.
The majority of first trimester miscarriages resolve spontaneously without causing any maternal morbidity or requiring treatment. However, because of their high incidence, miscarriages and the associated costs of investigation, hospital admission, treatment and follow-up are a significant burden. Miscarriage has a negative impact on the quality of life of women. It signifies a loss of a baby, even in early gestations, and is a stressful and sad time for the women and their partners.
The maternal mortality rates after miscarriage in the United Kingdom ranged from 0.05 to 0.22 per 100,000 pregnancies between 1985 and 2008. Haemorrhage and sepsis, which mainly occurred after second trimester losses, were the most common causes of death.
Definition of Miscarriage
Miscarriage is the spontaneous loss of an intrauterine pregnancy that occurs before 24 weeks’ gestation, the current limit of viability. Miscarriages have been described as early and late, with an early miscarriage occurring up to 12 weeks’ gestation and a late miscarriage occurring after 12 weeks’ and before 24 weeks’ gestation.
Aetiology of Early Miscarriage
Chromosomal Abnormalities
The majority of first trimester miscarriages are caused by chromosomal abnormalities. Chromosomal abnormalities are detected in up to 85% of pregnancy tissue analysed after a spontaneous miscarriage. Fetal malformations were seen in 85% of early miscarriages in a study that assessed fetal morphology by embryoscopy before surgical management. Roughly 70% of chromosomal abnormalities are accounted for by trisomies, and most trisomies involve chromosome 16, 21 and 22. An estimated 20% are accounted for by triploidies and 10% by monosomy X. The risk for miscarriage increases dramatically with increasing maternal age. The risk for miscarriage is up to 15% in women up to the age of 34 years. However, it increases to 25% at 35 to 39 years, 51% at 40 to 44 years and more than 90% in women aged 45 years and older. The risk for trisomies increases with maternal age, but the rate of nontrisomic and euploid miscarriages does not vary significantly with maternal age.
Maternal Medical Condition
The risk for miscarriage is higher in women with thyroid dysfunction and thyroid autoimmunity. The presence of thyroperoxidase antibodies was shown in a large meta-analysis to increase the risk for miscarriage significantly (odds ratio (OR), 3.73; 95% confidence interval (CI) 1.8–7.6). A large prospective study showed that the risk for miscarriage nearly doubled in women with a thyroid-stimulating level greater than 2.5 miU/L even in the absence of thyroperoxidase antibodies. The Thyroid AntiBodies and LEvoThyroxine (TABLET) trial is a large multicentre, double-blind, placebo-controlled trial currently being carried out in England and Scotland. The trial is looking at whether the chances of delivery beyond 34 weeks’ are increased in women who have thyroperoxidase antibodies but are euthyroid by taking 50 mcg of Thyroxine daily ( https://www.trials.bham.ac.uk/tablet ). The rate of miscarriage is also higher in women with diabetes mellitus, particularly if disease control is poor before conception.
Congenital Uterine Anomaly
A systematic review looking at the reproductive outcomes of women with congenital uterine anomalies showed that the presence of a uterine septum increases the risk for a first trimester miscarriage (risk ratio, 2.89; 95% CI, 2.02–4.14).
Lifestyle Factors
There is no proven association between miscarriage and smoking, and this was confirmed in a prospective study of 24,608 pregnancies. Obesity is linked with a greater risk for miscarriage. A systematic review with a cohort of 28,538 women showed that the miscarriage rate after spontaneous conception was higher in women with a body mass index (BMI) of 28 kg/m 2 or greater than in women with a BMI less than 25 kg/m 2 (13.6% vs 10.7%; OR,1.31; 95% CI, 1.18–1.46). A national Danish birth cohort study showed that alcohol increases the risk for miscarriage in even small amounts and that the risk increased with increasing alcohol consumption.
Clinical Symptoms and Findings of Miscarriage
Approximately one in five women experience vaginal bleeding and abdominal pain in the first trimester. The bleeding that women experience in early pregnancy can vary from vaginal spotting to severe haemorrhage causing shock. Vaginal bleeding and the loss of pregnancy symptoms can suggest a miscarriage, but miscarriage is not diagnosed clinically. Almost 50% of pregnancies that are complicated by bleeding in the early stages will continue to develop normally beyond the first trimester.
A miscarriage cannot be accurately diagnosed based on clinical symptoms and findings on vaginal digital and speculum examination alone. A transvaginal ultrasound should be performed to make an accurate diagnosis. A large Dutch study showed that a diagnosis of miscarriage made on clinical symptoms and findings was erroneous in more than 50% of cases. Another study showed that 40% of women who were diagnosed as having a complete miscarriage clinically were subsequently shown to have retained products of conception.
A speculum examination is necessary in women presenting with heavy vaginal bleeding or who show signs of haemodynamic instability because it may facilitate immediate removal of products of conception from the cervix. It can, however, be omitted in women who present with lighter bleeding because it does not aid in making an accurate diagnosis.
Ultrasound Diagnosis of Miscarriage
Transvaginal ultrasonography is the accepted primary investigation for suspected early pregnancy complications. The location and viability of a pregnancy have to be determined when performing an ultrasound scan in early pregnancy. The morphological appearance of pregnancy is the only criteria taken into account for an ultrasound diagnosis of a miscarriage. It is imperative to know the features of a normal intrauterine pregnancy in order to accurately diagnose early pregnancy complications.
Normal Intrauterine Pregnancy
A normal intrauterine pregnancy is located within the uterine cavity, which starts at the level of the internal cervical os and extends to the tubal ostia. The trophoblast should not extend beyond the endometrial–myometrial junction. The transvaginal probe is moved in the transverse plane from the internal os all the way to the fundus to identify an intrauterine pregnancy. The location of the gestation sac beneath the endometrial surface is seen in the longitudinal view. The intrauterine location of the gestation scan is finally confirmed by establishing a communication between the cervical canal and uterine cavity. Endometrial thickness does not aid in the diagnosis of a pregnancy’s location or viability. The cervix, caesarean section scar if present, myometrium and interstitial portions of the fallopian tubes are systematically assessed by moving the transvaginal probe from side to side and up and down.
In a pregnancy that is developing normally, a gestation sac is first visualised at 2 weeks and 3 days after conception, that is, at 4 weeks and 3 days in a woman with regular 28-day cycles ( Fig. 5.1 ). The gestation sac typically appears as circular structure with a thick echogenic outer rim and a clear anechoic centre, which signifies the early chorionic activity. The sac is buried into the decidualised endometrium, and its location is just below the midline echo. Myometrial cysts which are associated with adenomyosis may appear similar to an early gestation sac. Myometrial cysts are located beyond the endometrial–myometrial junction, allowing differentiation from a gestation sac. A pseudosac, which is an accumulation of blood within the uterine cavity, may also appear similar to a gestation sac. A pseudosac appears avascular on Doppler examination and is encircled by a single decidual layer. The shape of a pseudosac may also change during the scan. These features differ from that of a normal gestation sac, which has a stable shape, tends to demonstrate strong peripheral blood flow and is surrounded by a double decidual layer ( Fig. 5.2 ).
The mean gestation sac diameter is calculated by taking the average of three perpendicular diameters measured from the inner margin of the echogenic rim. The gestation sac grows roughly 1 mm per day in the early stages of pregnancy. The yolk sac can be visualised within the gestation sac from 5 weeks’ gestation. The technique of measuring the yolk sac is similar to that of the gestation sac but with the measurements taken from the middle of the yolk sac wall. The embryo is first visible at 5 weeks and 5 days’ gestation. The embryo at its early stages typically appears as a linear echogenic structure next to the yolk sac. The vitelline duct connects the embryo to the yolk sac. The crown (head) can be distinguished from the rump (trunk) from 7 weeks’ gestation ( Fig. 5.3 ). The crown-length measurement should be made in the sagittal section of the embryo, ensuring the yolk sac is excluded in the measurement.
Embryonic cardiac activity can be visualised from 5 weeks and 5 days’ gestation, when the embryo measures 2 to 5 mm in length. It is vital not to misinterpret background movement and maternal pulsation as embryonic cardiac activity. The heart rate should be measured using M-mode ( Fig. 5.4 ). Pulsed Doppler examination should not be used in the first trimester because it produces high-energy acoustic output. It has been reported that a heart rate below 100 beats/min is suggestive of a pregnancy that is not developing normally. The heart rate could, however, be below 100 beats/min in an early normal pregnancy and then rise rapidly around 6 to 7 weeks’ gestation. The amniotic sac becomes visible from 7 weeks’ gestation.
The amniotic sac should be measured in a similar manner to the yolk sac, with the measurement taken from the middle of the amniotic sac wall. The spine and rhombencephalon can be distinguished and the umbilical cord can be visualised from 7 weeks’ gestation. The forebrain, midbrain, hindbrain and skull are evident at 8 weeks’ gestation. At the same time, the limb buds start to grow, the amniotic sac expands, the vitelline duct and umbilical cord lengthen and a midgut hernia becomes apparent.
Multiple Pregnancy
The first evidence of a multiple pregnancy is the presence of more than one gestation sac around 5 weeks’ gestation. There is not always a correlation between the number of embryos in a multiple pregnancy with the number of gestation sacs and yolk sacs. The entire gestation sac needs to be systematically examined when the pregnancy progresses beyond 6 weeks’ gestation to ensure that all embryos present are detected. The amnion is seen separate to the embryo at 7 weeks’ gestation, and this is when amnionicity should be assessed. The chorion and amnion are not fused at this stage, and the chorionicity and amnionicity can be accurately established.
Early Embryonic Demise
Early embryonic demise describes the early stage in the course of a miscarriage. An intact gestation sac is still visible within the uterine cavity, and there is either no embryo present within the gestation sac or there is no cardiac activity in a visualised embryo ( Fig. 5.5 ). The main challenge in to avoid confusing a normal early pregnancy with a miscarriage. The risk for diagnostic error is significant when making a diagnosis of early embryonic demise because the diagnosis is based on negative findings. Women who have irregular menstrual cycles, are unsure of the date of their last menstrual period, have conceived while on hormonal contraception or have conceived having had less than three menstrual periods since their last pregnancy are at increased risk for being given a wrong diagnosis. The risk for diagnostic error is also greater in the presence of congenital uterine anomalies, uterine fibroids, adhesions after abdominal surgery, altered uterine position after pelvic surgery and a retroverted uterus.
A wide range of cut-off points for the size of the embryo and gestation sac to be used when making a diagnosis of early embryonic demise have been proposed over the years. The 2012 National Institute of Clinical Excellence (NICE) guideline on the diagnosis and initial management of ectopic pregnancy and miscarriage recommends that an early embryonic demise should be suspected when the mean sac diameter is 25.0 mm or greater and there is no visible embryo and when the crown–rump length is 7.0 mm or greater and there is no visible cardiac activity. The guideline also recommends that a second opinion on the viability of the pregnancy is sought or a repeat scan is performed 7 to 14 days later before making a confirmed diagnosis of a miscarriage. The reason for this is that the chief cause of misdiagnosis is operator error, and this can occur with any cut-off value.
Incomplete Miscarriage
Incomplete miscarriage describes the presence of products of conception within the uterine cavity in the absence of an intact gestation sac. It can be sometimes difficult to differentiate trophoblastic tissue from blood clots within the uterine cavity, which are often present in women who are bleeding. Retained products of conception are typically seen as hyperechoic tissue which is well defined and shows increased vascular blood flow on colour Doppler examination ( Fig. 5.6 ). Contrastingly, blood clots appear avascular on colour Doppler examination and are not well defined. It is challenging to diagnose an incomplete miscarriage, and currently there are no accepted criteria for making the diagnosis.
Complete Miscarriage
Complete miscarriage is diagnosed when there is no evidence of pregnancy tissue within the uterine cavity. The diagnosis can only be made if there has been a previous ultrasound scan confirming an intrauterine pregnancy. The pregnancy should be described as inconclusive or nondiagnostic if the pregnancy has not been confirmed to be intrauterine previously.
Prediction of Miscarriage
Ultrasound Features
The presence of embryonic cardiac activity at the first ultrasound scan does not always indicate that the pregnancy will develop normally. There are morphological features which suggest the pregnancy may not develop normally, and assessment of these features allows appropriate counselling. These features are, however, not diagnostic of a miscarriage, and further assessment of the pregnancy is usually required. The morphological features suggestive of an increased risk for early pregnancy failure include an irregular gestation sac ( Fig. 5.7 ); a gestation sac with a thin trophoblastic layer; the presence of an amniotic sac and the absence of embryonic cardiac activity; a disproportionately large gestation sac, yolk sac or amniotic sac relative to the size of the embryo; a discrepancy between the gestational age based on the crown–rump length and the gestational age based on the last menstrual period; and an embryonic heart rate below the fifth centile for gestational age or less than 85 beats/min.
Biochemical Markers
Biochemical markers play a role in cases in which the ultrasound scan is nondiagnostic but are not routinely used to diagnose early pregnancy failure. Human chorionic gonadotrophin (hCG) levels in maternal serum double every 1.4 to 1.6 days from the point of first detection to the 35th day of pregnancy and double every 2.0 to 2.7 days from the 35th to the 42nd day of pregnancy. Slower hCG doubling times is associated with miscarriage, and declining hCG levels is highly accurate in diagnosing a complete miscarriage after an inconclusive scan. A serum progesterone level below 16 nmol/L is highly suggestive that the pregnancy is not viable, but a diagnosis of miscarriage should not be made based on a progesterone level alone.
Management of Miscarriage
Expectant Management
Expectant management has become an increasingly popular option over the past decade or so and is chosen by women who desire a natural approach. The primary disadvantage with expectant management is uncertainty over the timescale and final outcome.
Expectant management via the use of placebo has been shown in randomised trials to be successful in 29% to 42% of women with an early embryonic demise up to 12 weeks’ gestation and 55% to 86% of women with an incomplete miscarriage. Expectant management was shown to have a higher rate of unplanned emergency intervention (35% vs 18%; relative risk (RR), 2.28; CI, 1.93–2.7) and higher rate of blood transfusion (1.6% vs 0.4%; RR 3.39; CI, 1.08–10.61) compared with active management (medical or surgical) in a meta-analysis of published studies. There was, however, no significant difference in infection rates.
The 2012 NICE guideline on the diagnosis and initial management of ectopic pregnancy and miscarriage recommends that women be offered expectant management for 7 to 14 days as first-line management. Waiting for longer than 2 weeks is not risky as long as there are no signs of infection, and the chances of complete resolution increase with length of follow-up.
Medical Management
Medical management avoids the need for surgery and the associated risks in more than 70% of women with an early embryonic demise up to 12 weeks’ gestation. The success rates of medical management of an incomplete miscarriage are also high but do not differ significantly comparison with expectant management. Approximately 20% to 30% of women choose to have medical management.
The prostaglandin analogue misoprostol is the most commonly used drug in medical management. It can be administered in single or divided doses and via the oral, vaginal, sublingual or rectal route but is only licensed for use orally. The use of mifepristone, an antiprogesterone drug, before the administration of misoprostol does not increase the success rates significantly. The main side effects with the use of misoprostol are nausea, fever, diarrhoea and vomiting. Bleeding typically starts within a few hours of misoprostol’s being administered. The bleeding can, however, continue for up to 3 weeks, and women should be reassessed if they bleed for longer than 3 weeks. One percent of women undergoing medical management will require emergency surgery because of heavy bleeding.
Surgical Management
Surgical management can be performed by suction curettage in an operating theatre under general anaesthesia or by manual vacuum aspiration in the outpatient setting under local anaesthesia. Women can be offered surgical management on an elective basis unless they present with excessive vaginal bleeding, demonstrate signs of haemodynamic instability or show signs of having infected retained products of conception. Surgical management is the management of choice in women suspected of having gestational trophoblastic disease.
A meta-analysis of clinical trials showed that women undergoing medical management had a higher unplanned intervention rate (21.3% vs 2.5%; RR, 8.13; CI, 6.26–10.55) compared with women undergoing surgical management. Women also bled for longer when they chose to have medical instead of surgical management (median, 11.0 vs 8.0 days). The rates of infection and blood transfusion were not significantly different with surgical or medical management.
The complications with surgery include cervical laceration, uterine perforation, excessive bleeding and intrauterine adhesions. The rates of these complications are 2% to 8%.
Recurrent Miscarriage
Recurrent miscarriage, which is defined as three or more consecutive miscarriages, affects 1% of women of reproductive age. The risk for a further miscarriage is approximately 40% after three consecutive pregnancy losses. Women can experience recurrent miscarriage despite having a previous live birth. Chromosomal abnormalities are the overriding reason for early pregnancy loss. In around 4% of couples with a history of recurrent miscarriage, at least one partner will carry a chromosomal anomaly. The chromosomal anomaly may be a balanced or Robertsonian translocation, and the carrier is phenotypically normal. Approximately 50% to 70% of gametes will inherit an unbalanced chromosomal complement during meiosis, resulting in a chromosomally abnormal embryo. Antiphospholipid syndrome, which describes the association between antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies and anti-B 2 glycoprotein-I antibodies) and vascular thrombosis or adverse pregnancy outcomes, is the most treatable cause of recurrent miscarriage. Adverse pregnancy outcomes include three or more consecutive miscarriages before 10 weeks’ gestation, loss of one or more morphologically normal fetus after 10 weeks’ gestation and one or more preterm deliveries of a morphologically normal fetus before 34 weeks’ gestation because of placental insufficiency. Antiphospholipid antibodies are present in 15% of women with recurrent miscarriage and only in 2% of women with a low-risk obstetric history. The risk for miscarriage in a subsequent pregnancy is as high as 90% without pharmacological treatment. A combination of aspirin and unfractionated heparin has been shown to increase the chances of a live birth to 70%. There is a fourfold higher prevalence of congenital uterine anomalies in women with recurrent miscarriage compared with women with a low-risk obstetric history according to studies that used three-dimensional ultrasound to detect uterine anomalies. The congenital uterine anomalies are also more severe in the recurrent miscarriage group compared with the low-risk group. A large meta-analysis showed an association between factor V Leiden, activated protein C resistance, prothrombin gene mutation and protein S deficiency and recurrent miscarriage.
Molar Pregnancy
Molar pregnancy is a diagnosis made histologically and can be divided into complete and partial moles according to histologic and genetic features. Roughly 80% to 95% of complete molar pregnancies are detected on ultrasound. Thick and cystic tissue within the uterine cavity without evidence of a gestation sac is suggestive of a complete molar pregnancy ( Fig. 5.8 ). An intact gestation sac with cystic placental changes raises the suspicion of a partial molar pregnancy. Only 20% to 30% of partial molar pregnancies are detected on ultrasound. An accurate and early diagnosis allows the appropriate management and follow-up, and this is important because of the possibility of gestational trophoblastic neoplasia (persistent gestational trophoblastic disease, invasive hydatidiform mole, choriocarcinoma and placental site trophoblastic tumour). The incidence in the United Kingdom of gestational trophoblastic disease, which includes molar pregnancy and gestational trophoblastic neoplasia, is 1 per 714 live births. Complete moles are androgenic and almost always diploid. They arise mainly after reduplication without cell cytokinesis after monospermic fertilisation or more rarely from dispermic fertilisation of an anucleate oocyte. Partial moles almost always occur after dispermic fertilisation of an ovum. The majority of molar pregnancies present with clinical signs and ultrasound findings of early pregnancy failure. Suction curettage ideally under ultrasound guidance is the recommended management of a molar pregnancy. Products of conception must be sent for histologic examination to make a diagnosis. All women with a molar pregnancy need to be registered with a Gestational Trophoblastic Disease Screening Centre for serial measurement of serum or urine hCG. About 5% to 8% of women with gestational trophoblastic disease require chemotherapy for persistent disease.
Ectopic Pregnancy
An ectopic pregnancy is any pregnancy that implants outside the uterine cavity. The prevalence of ectopic pregnancy in the United Kingdom is 1.1% with nearly 12,000 ectopic pregnancies diagnosed each year. Women undergoing in vitro fertilisation have a higher ectopic pregnancy rate of up to 2%. The maternal mortality rate is 0.2 per 1000 cases of ectopic pregnancies. Even though the mortality rate is very low, expensive diagnostic tests and treatment prove a significant burden.
A total of 93% to 98% of ectopic pregnancies implant within the fallopian tubes, making the fallopian tubes the most common site for an ectopic pregnancy. As a result, the terms ectopic pregnancy and tubal pregnancy are often used interchangeably.
A total of 5% to 7% of ectopic pregnancies implant outside the uterine cavity but within the walls of the uterus. The ‘nontubal’ ectopic pregnancies include cervical, caesarean section scar, intramural and interstitial pregnancies. Ectopic pregnancies outside the tubes and uterus include ovarian and abdominal pregnancies. These ectopic pregnancies are more difficult to diagnose than tubal pregnancies. This often leads to a delay in diagnosis and late presentation after sudden rupture. The mortality rate is consequently high with ‘nontubal’ ectopic pregnancies. Interstitial ectopic pregnancies are particularly associated with a high mortality rate and account for almost 20% of all deaths from an ectopic pregnancy despite making up only 2.5% of all ectopic pregnancies.
A heterotopic pregnancy is a concomitant intrauterine and extrauterine pregnancy. It occurs in 0.3% to 0.8% spontaneous pregnancies and 1% to 3% of pregnancies after assisted reproductive techniques.
Risk Factors for Ectopic Pregnancy
A previous ectopic pregnancy, evidence of tubal pathology, previous tubal surgery and exposure to diethylstilboestrol are strongly associated with ectopic pregnancy. Moderate risk factors for ectopic pregnancy include a history of genital infections, including Chlamydia and gonorrhoea, infertility and multiple sexual partners.
A large French case-control study identified women who are smokers or ex-smokers and women who have been previously been diagnosed with a sexually transmitted disease to have a significantly increased risk for developing an ectopic pregnancy. Other risk factors identified in this study are previous tubal surgery, history of infertility and increased maternal age. However, roughly 24% of women who were diagnosed with an ectopic pregnancy in the study from France had no identifiable risk factors.
All forms of contraception reduce the risk for an ectopic pregnancy because they reduce overall pregnancy rates. The risk for developing an ectopic pregnancy when contraception fails varies depending on the method of contraception used. The risk for ectopic pregnancy is particularly high in women who become pregnant after tubal ligation (OR, 9.3; 95% CI, 4.9–18.0). The 10-year cumulative risk for ectopic pregnancy after tubal ligation was shown to be 7.3 per 1000 procedures in a multicentre prospective cohort study. The risk for ectopic pregnancy is also significantly increased in women who have an intrauterine contraceptive device in situ (OR, 10.6; 95% CI, 7.66–10.74). About 6% to 10% of women who become pregnant while on the progesterone-only pill develop an ectopic pregnancy.
The risk for ectopic pregnancy in women who use the combined oral contraceptive pill, condoms or emergency hormonal contraception is similar to women not using any contraception.
Clinical Symptoms and Findings of Ectopic Pregnancy
The clinical presentation of ectopic pregnancy is variable. Women with an ectopic pregnancy have been described as presenting with the triad of amenorrhoea, vaginal bleeding and pelvic or abdominal pain. This is, however, not always the case, and one study showed that around 30% of women with an ectopic pregnancy did not present with this triad. Vaginal bleeding in the form of brownish vaginal discharge is typically the earliest symptom, which often starts soon after the missed menstrual period. The vaginal bleeding can occasionally be heavy, and this can lead to the misdiagnosis of a miscarriage. A total of 10% to 20% of women with an ectopic pregnancy do not experience vaginal bleeding.
Abdominal pain is often a late symptom and usually occurs because of tubal distension, bleeding through the fimbrial end into the peritoneal cavity from tubal miscarriage or tubal rupture. Abdominal pain from tubal rupture tends to be more intense, and abdominal palpation may detect signs of peritonism. Shoulder tip pain, which characteristically reflects irritation of the diaphragm, is a sign of major intraabdominal bleeding. Nearly 10% of women with an ectopic pregnancy do not develop abdominal pain.
Severe intraabdominal bleeding can cause nausea, vomiting and diarrhoea, which can erroneously suggest a gastrointestinal (GI) disorder and delay the diagnosis of a ruptured ectopic pregnancy. In the 2006 to 2008 Confidential Enquiry into Maternal and Child Health (CEMACH) report, four of six women who died from an ectopic pregnancy since 1997 were misdiagnosed initially as having a GI disorder. A key recommendation from the last two CEMACH reports is that sudden GI symptoms should alert to the possible diagnosis of ectopic pregnancy.
The diagnostic benefit of vaginal examination including speculum examination and bimanual palpation of pelvic organs is limited. A vaginal examination has traditionally been performed as part of the assessment when an early pregnancy complication is suspected. The findings of cervical motion tenderness, adnexal tenderness or an adnexal mass are nonspecific signs which do not aid in making a diagnosis. A total of 36% of women with an ectopic pregnancy lack adnexal tenderness on vaginal examination. A transvaginal ultrasound should be the primary investigation carried out.
Ultrasound Diagnosis of Ectopic Pregnancy
Criteria for the diagnosis of an ectopic pregnancy were first described in 1969. An ectopic pregnancy was initially suspected when there was no conclusive evidence of an intrauterine pregnancy on scan. High-resolution transvaginal ultrasound has changed the diagnostic approach to the direct visualisation of the ectopic pregnancy ( Figs. 5.9 and 5.10 ). Transabdominal scanning is inferior to transvaginal scanning in the diagnosis of an ectopic pregnancy with early studies showing that the sensitivity with the transabdominal approach is 77% to 80% and the sensitivity with the transvaginal approach is 88% to 90%. The sensitivity with transvaginal scanning has increased further as the ultrasound machines and expertise of operators have improved.
