Materials and Methods

We conducted a retrospective cohort study that included all pregnancies from 2005 through 2008 in the state of California. The data for these calculations were derived from linked mother-infant datasets from the California Vital Statistics Birth Certificate Data, Vital Statistics Death Certificate Data, California Patient Discharge Data, and Vital Statistics Fetal Death File. Data linkage is performed by the California Office of Statewide Health Planning and Development Healthcare Information Resource Center, under the California Health and Human Services Agency, with the use of a unique record linkage number specific to the mother-infant pair. The state of California maintains these linked datasets that include health information from maternal antepartum and postpartum hospital records for the 9 months before delivery and 1 year after delivery, as well as birth records and all infant admissions that occur within the first year of life. We obtained human subjects approval from the Institutional Review Board at Oregon Health & Science University, the California Office of Statewide Health Planning and Development, and the Committee for the Protection of Human Subjects. The linked dataset did not contain potential patient privacy/identification information, so informed consent was exempted.

Our primary exposure of interest was a diagnosis of methamphetamine use during the pregnancy; we identified 8542 women with pregnancies that were associated with methamphetamine use with the use of the following International Classification of Diseases, 9th Revision (ICD-9) codes: 304.4, 304.40 (dependence, unspecified use), 304.41 (dependence, continuous use), 304.42 (dependence, episodic use), 305.70 (nondependent abuse, unspecified use), 305.71 (nondependent abuse, continuous use), 305.72 (nondependent abuse, episodic use), and 969.72 (poisoning by amphetamines). These 8542 cases were compared with 2,031,328 control pregnancies. To avoid the confounding of complications linked to multifetal gestations and congenital anomalies, we excluded these pregnancies for both the case group and the control group. Analyses were conducted with Stata software (version 12; StataCorp, College Station, TX) and R software (version 2.13.1; R Foundation for Statistical Computing, Vienna, Austria).

Outcomes of interest that we examined were also determined retrospectively through the use of ICD-9 codes and included gestational hypertension, preeclampsia, pregnancy-associated hypertension (defined as gestational hypertension or preeclampsia), severe preeclampsia, severe preeclampsia among those with pregnancy-associated hypertension, eclampsia, abruption, intrauterine fetal death, preterm delivery (<37 weeks 0 days), very preterm delivery (<32 weeks 0 days), small for gestational age, birthweight <2500 g, birthweight >4000 g, gestational diabetes mellitus, neonatal death, infant death, and neonatal jaundice among those born preterm. Statistical comparisons of categoric variables were made with chi-squared tests. Potential confounders that included maternal age (≥35 and <20 years old), maternal education (>12 vs ≤12 years), insurance status (private insurance vs public insurance or no insurance), race/ethnicity, parity, diabetes mellitus, chronic hypertension, gestational diabetes mellitus, tobacco use, and alcohol use were controlled for with the use of multivariable logistic regression analyses and excluded those variables that were used as the outcome of interest when appropriate. For example, we did not adjust for gestational diabetes mellitus when we evaluated gestational diabetes mellitus as an outcome. Those women with exposure to cocaine, opioids, and/or cannabis were also excluded from analysis. Statistical significance was determined by a probability value of < .05 and/or 95% confidence intervals (CIs).

Results

With the use of methods described earlier, 8542 pregnancies (0.4%) that were linked to a diagnosis of methamphetamine use were identified and compared with 2,031,328 control pregnancies. Demographic data for the 2 groups is listed in Table 1 . In unadjusted analysis ( Table 2 ), there was a statistically significant increase in hypertensive diseases of pregnancy associated with methamphetamine use. Compared with control pregnancies, methamphetamine users had a greater frequency of pregnancy-associated hypertension (11.6% vs 5.8%; P < .001), gestational hypertension (5.6% vs 3.2%; P < .001), preeclampsia (6.8% vs 2.9%; P < .001), severe preeclampsia (2.5% vs 0.8%; P < .001), and eclampsia (0.3% vs 0.1%; P < .001). Furthermore, among those women who were diagnosed with pregnancy-associated hypertension, the percentage who went on to experience severe preeclampsia was 21.6% among methamphetamine users vs 13.5% among control subjects ( P < .001).

Gestational age at delivery was also associated with the use of methamphetamine. Preterm birth, which was defined as delivery at <37 weeks 0 days of gestation (23.4% vs 8.9%; P < .001), and very preterm birth, which was defined as delivery at <32 weeks 0 days of gestation (5.3% vs 1.2%; P < .001), both were increased significantly among methamphetamine users when compared with control subjects.

Methamphetamine use was associated with increased incidence of small-for-gestational-age neonates, when compared with control subjects (18.2% vs 10.6%; P < .001), and birthweight <2500 g (17.2% vs 5.0%; P < .001).

Methamphetamine users were found to have a higher incidence of abruption (5.2% vs 0.8%; P < .001) and intrauterine fetal death (1.4% vs 0.3%; P < .001). Neonatal death was increased among neonates who were born to methamphetamine users at term (0.5% vs 0.1%; P < .001), yet this increase in neonatal death was not significant for preterm neonates (2.1% vs 1.6%; P = .07). However, when we looked at the data for all neonates combined, regardless of gestational age at delivery, there was again a statistically significant increase in neonatal death with maternal methamphetamine use (0.8% vs 0.2%; P < .001). Infant death also showed a significantly increased incidence among children who were born at term to methamphetamine users (0.4% vs 0.1%; P < .001) and among infants who were born preterm (0.6% vs 0.3%; P < .001). This increase remained significant when we looked at the data for all infants together, regardless of gestational age at birth (0.4% vs 0.1%; P < .001). Finally, maternal methamphetamine use during pregnancy was found to be associated with a lower incidence of jaundice among neonates who were born prematurely, although this finding was not statistically significant (25.7% vs 27.0%; P = .16).

Methamphetamine use appeared to be protective against macrosomia and gestational diabetes mellitus. The incidence of birthweight <4000 g was decreased significantly among neonates who were born to methamphetamine users (4.5% vs 8.8%; P < .001) as was the incidence of gestational diabetes mellitus (2.7% vs 6.1%; P < .001) among those mothers who delivered at term.

The same cohort of findings that were statistically significant on unadjusted analysis remained statistically significant after the exclusion of those who were exposed to cocaine, opioids, and cannabis and when multivariable regression analysis adjusted for the following variables: ethnicity, maternal age (≥35 or <20 years old), nulliparity, maternal education (>12 or ≤12 years), insurance status (private insurance or public/no insurance), diabetes mellitus, gestational diabetes mellitus, chronic hypertension, tobacco exposure, and alcohol exposure ( Table 3 ). Those variables that were used as the outcome of interest appropriately were not controlled for, as outlined in the earlier.

Table 3

Adjusted odds ratios for outcomes among methamphetamine users vs control subjects ^a

Outcome of interest	Odds ratio	95% confidence interval
Preeclampsia	2.7	2.4–3.0
Severe preeclampsia	3.9	3.3–4.6
Eclampsia	4.4	2.6–7.3
Pregnancy-associated hypertension (gestational hypertension + preeclampsia)	2.3	2.2–2.5
Gestational hypertension	1.8	1.6–2.0
Gestational diabetes mellitus	0.4	0.4–0.5
Abruption	5.5	4.9–6.3
Intrauterine fetal death	5.1	3.7–7.2
Very preterm delivery (<32 wk)	4.5	4.0–5.1
Preterm delivery (<37 wk)	2.9	2.7–3.1
Birthweight
<2500 g	3.5	3.3–3.8
>4000 g	0.5	0.4–0.6
Neonatal death	3.1	2.3–4.2
Neonatal death adjusted for gestational age	0.7	0.5–1.1
Jaundice adjusted for gestational age	1.1	1.0–1.1
Infant death	2.5	1.7–3.7
Infant death adjusted for gestational age	1.8	1.1–2.7

Gorman. Methamphetamine use in pregnancy. Am J Obstet Gynecol 2014 .

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Abdominal wall endometriosis: 12 years of experience at a large academic institution
2. Triploid pregnancies: genetic and clinical features of 158 cases
3. Infectious morbidity is higher after second-stage compared with first-stage cesareans
4. Indocyanine green for intraoperative localization of ureter

Stay updated, free articles. Join our Telegram channel

Join