Use of drugs to treat symptoms and acute conditions during pregnancy in outpatient care in Switzerland


BACKGROUND: Evidence on the use of drugs during pregnancy in Switzerland is lacking.
OBJECTIVES: To evaluate utilisation of prescribed drugs during pregnancy in outpatient care in Switzerland, focusing on treatments for pain, infections, gastro-oesophageal reflux, nausea/vomiting, and constipation.
METHODS: We conducted a descriptive study using the Swiss Helsana claims database (2014–2018). We established a cohort of pregnancies by identifying deliveries and estimating the date of the last menstrual period. We identified claims for the following drugs during pregnancy; analgesics (opioids, paracetamol, and nonsteroidal anti-inflammatory drugs [NSAIDs]), oral antibiotics, antacids, proton pump inhibitors (PPIs), anti-nausea drugs (propulsives and 5HT3-antagonists), and laxatives. Within these drug groups we quantified exposure prevalence to the most prescribed drugs (to >1% of pregnancies) during pregnancy as well as to specific potentially teratogenic or fetotoxic drugs during specific risk periods. Results were extrapolated relative to the demographic distribution of the Swiss population.
RESULTS: We identified an extrapolated population of 369,371 pregnancies, with a weighted mean maternal age of 32.0 years (weighted standard deviation 5.1). Analgesics were claimed in 34.5% (95% confidence interval [CI] 33.9–35.0%) of pregnancies, most frequently paracetamol (30.3%, 29.8–30.8%), followed by NSAIDs (8.6%, 8.3–8.8%), and opioids (2.6%, 2.4–2.8%). NSAIDs were claimed in 1.3% (1.2–1.4%) of pregnancies after week 24, and opioids were claimed in 1.3% (1.2–1.4%) in trimester 3. Antibiotics were dispensed in 26.3% (25.8–26.8%) of pregnancies, most frequently amoxicillin (14.6%, 95% CI 14.2–14.9%). Claims for potentially teratogenic or fetotoxic antibiotics during risk periods were each recorded in <0.6% of pregnancies. PPIs were claimed in 16.0% (15.6–16.3%) and antacids in 10.6% (10.3–11.0%) of pregnancies, but several antacid products are not reimbursed and thus not present in insurance claims. Anti-nausea drugs were claimed in 16.4% (16.0–16.7%) of pregnancies, most frequently metoclopramide in 14.4% (14.0–14.7%). Ondansetron was mainly dispensed in trimester 1, 1.0% (0.9–1.1%). In total, 6.4% (6.2–6.7%) of pregnancies had a claim for laxatives, most frequently for macrogol (2.4%, 95% CI 2.2–2.5%).
CONCLUSION: The observed pattern of claimed drugs during pregnancy is in line with existing treatment guidelines. Exposure to potentially teratogenic and fetotoxic drugs was small, but given the lack of recorded diagnosis, we cannot determine if their use was clinically indicated.


Pregnant women are typically excluded from interventional trials. Therefore, the safety of most drugs during pregnancy is not well characterised [1–4]. Nevertheless, many women require treatment of acute conditions, chronic illnesses, or obstetric complications during pregnancy. A study based on French national claims data reported that 90% of women filled at least one prescription for a drug during pregnancy between 2010 and 2013 [5], whereas 62% of pregnant women in Norway billed at least one drug to national health insurance between 2005 and 2015 [6]. In a multinational web-based survey [7], 81.2% of pregnant women reported using at least one drug, prescribed or over the counter (OTC), during pregnancy between 2011 and 2012. A total of 618 Swiss women took part in the survey, of whom 82.8% reportedly used at least one drug during pregnancy. However, these results may not be representative due to volunteer bias. The most frequently reported drugs were similar in all studies [5–7] and included analgesics (mainly paracetamol), antibiotics, drugs for gastro-oesophageal reflux disease and drugs for functional gastrointestinal disorders (mainly treatment of nausea). Iron, vitamins and folic acid were the most commonly used supplements.
We aimed to evaluate the utilisation of prescription drugs dispensed in outpatient care during pregnancy in Switzerland, using the data of the Helsana claims database. This study focuses on the utilisation of drugs (including potentially teratogenic/fetotoxic drugs) to treat acute conditions that frequently occur during pregnancy, such as pain of different origins, infections, gastro-oesophageal reflux, nausea and vomiting, and constipation. Utilisation of drugs to treat chronic illnesses will be evaluated in a separate study.


Data source

We conducted a descriptive study using data from the Swiss Helsana claims database between January 2014 and December 2018. The Helsana claims database includes data of approximately 1.1 million individuals from all 26 cantons in Switzerland (approximately 15% of the Swiss population) who are insured with Helsana mandatory insurance.
Recorded information includes outpatient medical encounters coded by the tariff system (TARMED), information on inpatient stays coded as Swiss Diagnosis Related Group (SwissDRG) codes as well as billing codes submitted by outpatient midwives. Furthermore, all reimbursed claims for drugs (recorded as Anatomical Therapeutic Chemical [ATC] codes) dispensed in outpatient care are captured [8].

Pregnancy cohort

Identification of pregnancies and delivery dates

This study population of pregnant women has been described previously [9]. To identify pregnancies, we captured all inpatient and outpatient deliveries between 2014 and 2018 using the SwissDRG, TARMED and midwife billing codes. Delivery codes that were recorded within 30 days following the first recorded delivery code were considered as pertaining to the same delivery and the date of the first record was defined as the delivery date. A delivery code recorded more than 300 days after an initial delivery code was considered as pertaining to a subsequent delivery. When two subsequent codes were separated by 30 to 300 days, the date of delivery was set at the SwissDRG code, whereas women (n = 80, crude number) were excluded if no SwissDRG code was recorded (fig. 1, flowchart of the unextrapolated study population). Thus, the same woman may have contributed several pregnancies to the cohort. Deliveries of twins were identified in the same way as deliveries of singletons and were counted as a single pregnancy.

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