Estimating the Beginning of Pregnancy in German Claims Data: Development of an Algorithm With a Focus on the Expected Delivery Date

BACKGROUND: Estimating the beginning of pregnancy is crucial when studying drug safety in pregnancy, but important information in this regard, such as the last menstrual period (LMP), is generally not recorded in claims databases. The beginning of pregnancy is therefore usually estimated by subtracting a median length of pregnancy from the date of birth. Due to the variability in pregnancy lengths, this might result in non-negligible errors. German claims data may offer the possibility to estimate the beginning of pregnancy more precisely based on the expected delivery date (EDD) which can be coded once or more often during a pregnancy. PURPOSE: To estimate the beginning of pregnancy in German claims data focusing on the potential of the expected delivery date (EDD). METHODS: We included data of all pregnancies in women aged 12–50 years ending in a live birth between 2006 and 2015 identified in the German Pharmacoepidemiological Research Database (GePaRD). We assessed the number of coded EDDs per pregnancy and the concordance if ≥ 2 EDDs were coded. We estimated the beginning of pregnancy by subtracting 280 days from the EDD or the most frequent EDD (in case of discordant EDDs). To examine plausibility, we determined the distribution of pregnancy lengths and assessed whether the gestational age at which prenatal examinations were coded was plausible. For pregnancies without EDD, the beginning was estimated by subtracting the respective observed median lengths of pregnancy for preterm births, term births, and births after due date from the actual dates of birth. RESULTS: In 82.4% of pregnancies, at least one EDD was available (thereof 6.1% with only one EDD and 80.9% with ≥ 2 EDDs that were all concordant). The maximal difference between discordant EDDs was in median 5 days (interquartile range: 3–7 days). Based on the EDD, the median length of pregnancy was 276 days for term births and in 84.7% of pregnancies the second antibody screening test was performed in the recommended interval ± 2 weeks. In pregnancies without EDD the respective proportion was 84.9%. CONCLUSIONS: By using the EDD, the beginning of pregnancy can plausibly be estimated in German claims data

Investigating drug safety in pregnancy based on the German Pharmacoepidemiological Research Database (GePaRD): A proof-of-concept analysis on the association between valproate and spina bifida

PURPOSE: Large health-care databases are increasingly used for research on drug utilization and safety in pregnancy. For the German Pharmacoepidemiological Research Database (GePaRD), covering ~20% of the German population, algorithms have been developed to identify pregnancies, to estimate their date of onset and to link mothers to their babies. Using this methodology, we aimed to conduct a proof-of-concept analysis on the known association between valproate (VPA) exposure in early pregnancy and spina bifida in the exposed child. METHODS: We identified all pregnancies in GePaRD between 2006 and 2016 in women aged 12 to 50 years. To each VPA dispensation of these women, an exposure period was assigned, based on the dispensation date and the number of defined daily doses in the dispensed package. A pregnancy was classified as exposed to VPA in the critical time window if this exposure period overlapped with the first 55 days of pregnancy. Risk ratios were calculated for spina bifida in live births and induced abortions comparing VPA-exposed ones to all pregnancies. RESULTS: Overall, we identified 1 271 384 pregnancies fulfilling the inclusion criteria. Of these, 668 pregnancies (0.053%) were classified as exposed to VPA in the critical time window regarding spina bifida. An induced abortion accompanied by a diagnosis of spina bifida was observed in one of the VPA-exposed pregnancies (0.15%) and in 154 of all pregnancies (0.012%), yielding a risk ratio of 12.4 (95% confidence interval [CI]: 1.7–88.2). Out of 775 875 pregnancies ending in a live birth, 366 (0.047%) were classified as VPA exposed. A diagnosis of spina bifida was coded in 3 of 366 VPA-exposed live births (0.82%) and in 260 of all live births (0.03%), yielding a relative risk of 24.5 (95% CI: 7.9–76.0). CONCLUSIONS: Our proof-of-concept analysis based on GePaRD showed a strong association between intrauterine exposure to VPA and occurrence of spina bifida. The results are plausible and consistent with the literature, supporting the suitability of GePaRD and the developed algorithms to conduct studies on drug safety in pregnancy

Effects of maternal modafinil treatment on fetal development and neonatal growth parameters - a multicenter case series of the European Network of Teratology Information Services (ENTIS)

Objective: In recent years, safety concerns about modafinil exposure during pregnancy have emerged. In particular, increased risks for major congenital anomalies (MCA) and impaired fetal growth were reported, although study results were conflicting. Our investigation aims to examine previously reported safety signals. Method: Multicenter case series based on data from 18 Teratology Information Services from 12 countries. Modafinil exposed pregnancies with an estimated date of birth before August 2019 were included in this study. For prospectively ascertained pregnancies, cumulative incidences of pregnancy outcomes, rate of nonchromosomal MCA in first trimester exposed pregnancies and percentiles of neonatal/infant weight and head circumference (HC) were calculated. Potential dose-dependent effects on fetal growth were explored by linear regression models. Retrospectively ascertained cases were screened for pattern of MCA and other adverse events. Results: One hundred and seventy-five prospectively ascertained cases were included, of which 173 were exposed at least during the first trimester. Cumulative incidences for live birth, spontaneous abortion and elective termination of pregnancy were 76.9% (95% CI, 68.0%-84.8%), 9.3% (95% CI, 5.0%-16.9%), and 13.9% (95% CI, 8.1%-23.1%), respectively. Nonchromosomal MCA was present in 3/150 live births, corresponding to an MCA rate of 2.0% (95%CI, 0.6%-6.1%), none were reported in pregnancy losses. Compared to reference standards, birth weight (BW) tended to be lower and neonatal HC to be smaller in exposed newborns (data available for 144 and 73 of 153 live births, respectively). In nonadjusted linear regression models, each 100 mg increase of average dosage per pregnancy day was associated with a decrease in standard deviation score (SDS) of -0.28 SDS (95% CI, -0.45 to -0.10) for BW and of -0.28 SDS (95% CI, -0.56 to 0.01) for HC. Screening of 22 retrospectively reported cases did not reveal any specific pattern of MCA or other adverse outcomes. Conclusion: The results do not indicate an increased risk of MCA after in utero exposure to modafinil, but a tendency toward lower BW and reduced neonatal HC. However, these findings should be regarded as preliminary. Until further studies allow for a definite conclusion, modafinil should not be used during pregnancy.The Berlin Embryotox Center of Clinical Teratology and Drug Safety in Pregnancy is financially supported by the German Federal Institute for Drugs and Medical Devices (BfArM); included German study cases were obtained from the Embryotox cohort. The UK Teratology Information Service is funded by the UK Health Security Agency. The Dutch Teratology Information Service is funded by the Ministerie van Volksgezondheid, Welzijnen Sport Research Unit on Congenital Anomalies-UIAC & Spanish Teratology Information Services SITTE and SITE are financially supported by Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, of Spain.S