9: Contraception and sterilization

CHAPTER 9
Contraception and sterilization


Rasha S. Khoury1 and Danielle M. Roncari2


1Division of Family Planning and Global Women’s Health, Department of Obstetrics, Gynecology & Reproductive Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA


2Division of Family Planning, Department of Obstetrics and Gynecology, Tufts University School of Medicine, Boston, MA, USA


Background


In 2006, approximately 49% of pregnancies in the United States (US) were unintended with 43% ending in abortion [1]. Of these unintended pregnancies, 46% were in women reporting no birth control or inconsistent use during the month they became pregnant [2]. The most popular methods of birth control among US women using contraception are the pills and female sterilization at 27.5% and 26.6% respectively [3]. The most effective methods of birth control other than female and male sterilization are long‐acting reversible contraception methods (LARC) including IUC and the implant. In a prospective cohort study of nearly 1000 women, the Contraceptive Choice Project, LARC methods had an unintended pregnancy rate of 0.27 per 100 participants as compared to the pill, patch, and ring with a rate of 4.55/100 women [4]. When counseling women on birth control options, it is important to discuss method effectiveness, future pregnancy desire, a patient’s medical problems, her concern over particular methods, and method related side effects and risks.


Clinical questions


In order to address the issues of most relevance to your patient and to help in searching the literature for the evidence regarding contraception methods, you structure your clinical questions as recommended in Chapter 1.



  1. How should women be counseled around fertility desires, pregnancy spacing, and limiting?
  2. How is contraceptive effectiveness determined and what is the effectiveness of the most common methods?
  3. What are the US medical eligibility criteria for contraceptive use? What methods are women with a history of migraine and active tobacco use eligible for?
  4. Who are appropriate candidates for LARC methods? Can women with a history of sexually transmitted infections (STIs) safely use these methods?
  5. What are non‐LARC contraceptive options?
  6. What methods are available for permanent contraception (sterilization)?
  7. What are currently available methods of emergency contraception and does BMI alter effectiveness?
  8. What barrier methods are currently available and what is best practice for using these methods?

General search strategy


You begin to address these questions by searching for evidence in the common electronic databases such as the Cochrane Library and MEDLINE looking specifically for systematic reviews and meta‐analyses.


Searching for evidence synthesis: primary search strategy


_ Cochrane Library: _____________ AND (topic)


_ MEDLINE:


Critical Review of the Literature



  1. How should women be counseled around fertility desires, pregnancy spacing and limiting?

Search Strategy


MEDLINE: (pregnancy OR birth) AND (intention OR spacing); sterilization AND counseling.


Exploring women’s viewpoints toward future pregnancies is an integral component of contraceptive counseling. Schwartz et al. suggest we expand the framework around pregnancy intention from intending and not intending to become pregnant to “seeking pregnancy now, avoiding now, planning for future and avoiding forever” [5]. This allows a provider to better understand a patient’s life context and meet her needs. On both ends of the spectrum, a patient who is seeking pregnancy now or avoiding forever can be offered pre‐conceptual counseling and sterilization counseling respectively. For patients avoiding pregnancy now and planning pregnancy in the future a discussion of preferred timing is paramount, taking into consideration optimal pregnancy intervals for maternal and neonatal health, age, fecundity, fertility desires, health services access, family and community support, social and economic support, and individual preference. With respect to spacing after a live birth the WHO recommends a birth‐to‐pregnancy interval of at least 24 months but less than five years [6] (to achieve the primary outcome of risk reduction in maternal, perinatal, and infant adverse events) [79]. Data reviewed for the WHO consultation suggest the risk of prematurity, fetal death, small for gestational age and low birth weight are highest for birth‐to‐pregnancy intervals shorter than 18 months (or longer than 59 months). While the relationship between pregnancy intervals and maternal mortality is unclear, maternal morbidity does appear to be associated with very long pregnancy intervals (mainly preeclampsia) rather than very short intervals (where cesarean delivery is the only variable with a clear relationship to short pregnancy interval‐related adverse events, mainly uterine rupture) [7]. The WHO birth spacing recommendation is also consistent with the WHO/UNICEF recommendation for breastfeeding for at least two years.


It is important when discussing sterilization methods to impart their permanence (and correct any misperceptions of their reversibility), the possibility of future regret, and specific information about the procedures available including risk of failure. Information should be communicated in the patient’s primary language, adjusted for literacy, remain medically accurate, understandable, and unbiased. The decision to move forward with sterilization, as with any medical procedure, should involve informed consent (an understanding of the risks, benefits, and alternatives as well decision‐making free of coercion). Parity and age are no longer considered criteria for sterilization though regret is associated with sterilization of women younger than 30 [1012]. In addition to age at time of sterilization, external pressure by clinicians, partners, and others, has been correlated with post‐sterilization regret [10]. However, marital status, level of education and childlessness have not been correlated with regret. [10]. The 14‐years cumulative probability of regret among a cohort of US women sterilized when they were younger than 30 was found to be 20.3%, compared to 5.9% among women older than 30 [10]. Regret is also associated with unpredictable life events, such as a change in partner status, health status, or the illness/death of a child.


Risk of sterilization failure should factor into the counseling. The US Collaborative Review of Sterilization (CREST) study provided us with a cumulative 10‐years probability of pregnancy after sterilization of 18/1000 (highest after clip sterilization and lowest after unipolar coagulation and postpartum partial salpingectomy – bipolar coagulation, Filshie clips, and hysteroscopic occlusion were not assessed as they were not available at that time) [12]. Failure can occur due to undetected luteal pregnancy, occlusion/transection of an incorrect structure, development of a tuboperitoneal fistula, incomplete or inadequate occlusion, device migration or slippage, and spontaneous reanastamosis/recanalization of the cut tubal ends. While one third of post sterilization pregnancies in the CREST study were ectopic pregnancies (high relative risk), sterilization has an overall protective effect on the risk of ectopic pregnancy (absolute risk of 4/1000). Complications are incredibly rare (occurring in fewer than 0.5% of cases) [13, 14]. All women requesting sterilization should be counseled on the highly effective LARC with comparably low failure rates using the (levonorgestrel intrauterine system (LNG IUS): 0.2% pregnant at one year, and implant 0.05% pregnant at one year).



  1. 2. How is contraceptive effectiveness determined and what is the effectiveness of the most common methods?

Search Strategy


_ MEDLINE: (contraception OR birth control) AND effectiveness.


Many women aren’t able to determine the relative effectiveness of various birth control methods; yet most women cite effectiveness as the most important factor for choosing a contraceptive [15]. Understanding effectiveness is crucially important to making an informed choice regarding a birth control method.


Many factors contribute to overall effectiveness including the fecundity of both partners, the timing of intercourse in relation to the timing of ovulation, the method of contraception used, the intrinsic effectiveness of the contraceptive method, and the correct and continuous use of the method. The Pearl formula is one way to estimate pregnancy risk. This formula calculates a pregnancy rate per 100 women per year by dividing the number of pregnancies by the total number of months contributed by all couples, and then multiplying the quotient by 1200. Because with most methods pregnancy rates decrease with time as the more fertile or less careful couples become pregnant and drop out of the calculations, the Pearl formula does not reflect actual use. More commonly, rates of pregnancy among different methods are best calculated by reporting two different rates derived from multiple studies (i.e. the lowest rate) and the usual or typical rate.


Perfect use is the percentage of couples who have an unintended pregnancy during the first year of use despite using a method perfectly (both consistently and correctly). Among average couples (may not use a method consistently or correctly), typical use refers to the percentage who experience an unintended pregnancy during the first year of use. Typical use is a practical way to look at overall effectiveness when counseling patients as it more accurately reflects practice than perfect use [16]. Continuation at one year is another important component in assessing a method’s overall effectiveness.


In looking at the effectiveness across methods, many providers find it useful to arrange effectiveness from least to most effective. Methods that require consistent and correct use have a wide range of effectiveness. Depicted in Table 9.1 is the percentage of women experiencing an accidental pregnancy within the first year of use of a contraceptive method along with one year continuation [16].



  1. 3. What are the US medical eligibility criteria for contraceptive use? What methods are women with a history of migraine and active tobacco use eligible for?

Search Strategy


Table 9.1 Percentage of women experiencing an unintended pregnancy during the first year of typical use and the first year of perfect use of contraception and the percentage continuing use at the end of the first year in the United States































































































































Percentage of women experiencing an unintended pregnancy within the first year of use Percentage of women continuing use at one year
Method Typical use Perfect use
No method 85 85
Spermicides 28 18 42
Fertility awareness‐based methods 24
47
Standard days method
5
Two day method
4
Ovulation method
3
Symptothermal method
0.4
Withdrawal 22 4 46
Sponge

36
Parous women 24 20
Nulliparous women 12 9
Condom

Female (fc) 21 5 41
Male 18 2 43
Diaphragm 12 6 57
Combined pill and progestin‐only pill 9 0.3 67
Evra patch 9 0.3 67
NuvaRing 9 0.3 67
Depo‐Provera 6 0.2 56
Intrauterine contraceptives

ParaGard (copper T) 0.8 0.6 78
Mirena (LNG) 0.2 0.2 80
Implanon 0.05 0.05 84
Female sterilization 0.5 0.5 100
Male sterilization 0.15 0.10 100

Source: Trussell, 2011 [16].


_ MEDLINE: (medical eligibility criteria) AND (contraception); contraception AND migraine; contraception AND smoking.


When counseling women on their contraceptive options it is vital to consider their medical and psychosocial context. While counseling should focus on the efficacy of each method as well as the synergy between the method’s duration of action and the woman’s future fertility desires, coexisting medical conditions, tobacco, alcohol, drug use, and social stressors will impact the safety profile and effectiveness of any method. Is the woman safe to choose a female user dependent method?; a male user dependent method?; an irreversible method? Does she need the method to be discrete? Can she access health care services if she experiences adverse effects?


After a thorough medical history, the CDC’s US Medical Eligibility Criteria (USMEC) (2010) can be most helpful in presenting the safety profile for method initiation and continuation according to the individual woman’s medical and personal characteristics. The USMEC are available in English and Spanish on the CDC website free of charge in both narrative and chart/table form. More recently they have become available as a user‐friendly iPhone and iPad application available for free download [17].


For healthy young women under the age of 35 the CDC considers all contraceptive methods (hormonal and non‐hormonal) safe without restriction (USMEC category 1). The risk of cardiovascular disease increases with age and might increase with combined hormonal contraceptive (CHC – pill, patch, ring) use however in the absence of other adverse clinical conditions, data suggest CHCs can be used until menopause (at age 40 the USMEC for CHCs changes to a 2 but remains safe). For women with migraines without aura the initiation of any method is category 1 or 2 (advantages outweigh risks) under 35; for women 35 and older the initiation of estrogen containing methods is category 3 (theoretical or proven risks outweigh the advantages of using the method), progestin only pills and copper IUC (category 1) and Depo‐Provera (depot medroxyprogesterone acetate (DMPA)), implants and LNG IUC (category 2). It is important to take a thorough headache history to delineate headaches that are migrainous from those that are not. New headaches and changes in headache character should be evaluated. The USMEC for migraines without aura are for women without any other risk factors for stroke (risk of stroke increases with age, hypertension, and smoking). Among women with migraines those with aura (complex of neurologic symptoms that occur just before or at the onset of the migraine headache [18] have a higher risk of stroke than those without aura [1921] and those who use CHCs are 2–4 times as likely to have an ischemic stroke as non‐users with a history of migraine [20, 2225].

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Jul 19, 2020 | Posted by in GYNECOLOGY | Comments Off on 9: Contraception and sterilization
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