Antiviral Medication Use During Pregnancy and Preeclampsia Risk: A Swedish Study

A recent study from Sweden is shedding light on the potential association between the use of antiviral medications during pregnancy and the risk of developing preeclampsia. preeclampsia, a serious pregnancy complication characterized by high blood pressure and organ damage, affects 2-8% of pregnancies worldwide and can lead to significant health risks for both mother and child. The research,leveraging comprehensive data from Swedish national registers,aims to provide clarity on this important issue.

Swedish Registry Data Examines Antiviral Use and Preeclampsia

Researchers in sweden conducted a register-based study using data from several national sources, including the Swedish Medical Birth Register (MBR), the Swedish National Patient Register (NPR), the Swedish National Prescribed Drug Register (NPDR), and Statistics Sweden. The MBR, which has been collecting data on all births in Sweden as 1973, records information from the mother’s first antenatal visit through hospital discharge. The NPR provides data on the mother’s medical history, while the NPDR tracks all medications dispensed by Swedish pharmacies.

The study focused on women giving birth to their first child in Sweden between 2007 and 2019. Pregnancies ending in stillbirth after the 22nd gestational week were included, but twin pregnancies were excluded from the analysis. Gestational length at delivery was primarily calculated based on routine antenatal ultrasounds.

Did You Know? The Swedish Medical Birth Register has been collecting comprehensive data on births for over 50 years, providing a rich resource for epidemiological research.

Defining and Categorizing preeclampsia

Preeclampsia was identified using ICD-10 codes (O11, O14, O15 and O16) recorded in the NPR. The researchers distinguished between different preeclampsia outcomes based on gestational age at delivery and infant growth:

• Preeclampsia with early preterm delivery (before week 34)
• Preterm preeclampsia (before week 37)
• term preeclampsia (after week 37)
• preeclampsia with a small-for-gestational-age infant (SGA), defined as birthweight below two standard deviations of mean birthweight for gestational age and fetal sex.

Statistical Analysis Methods

The study presented population characteristics according to antiviral medication use, further categorizing women by the timing of their first dispensed prescription. Results were presented as unadjusted and adjusted odds ratios, with 95% confidence intervals. as a sensitivity analysis, the group unexposed to antiviral medications was divided according to HSV status, and logistic regression was used to explore differences in preeclampsia likelihood among the three groups.

All statistical analyses were performed using R Statistical Software.A p-value below 0.05 was considered statistically significant.

Pro Tip: Directed acyclic graphs (DAGs) are valuable tools for identifying potential confounders in observational studies, helping researchers to minimize bias in their analyses.

Addressing Confounders and Bias

Possible confounders were evaluated using a directed acyclic graph (DAG), considering clinical risk factors for preeclampsia from existing literature. The identified confounders included maternal age, BMI, country of birth, IVF use, smoking at the first antenatal visit, pre-gestational diabetes, chronic hypertension, chronic kidney disease, and systemic lupus erythematosus.

To further address potential bias, the researchers used inverse probability of treatment weighting (IPTW) to adjust for baseline characteristics between women who used antiviral medications and those who did not. Propensity scores were calculated using the exposure as the outcome, and covariate balance was assessed graphically. Missing BMI values were imputed using the mice R package with predictive mean matching (pmm), and the analysis was repeated for each imputed dataset.

Model fit and adjusted odds ratios were calculated for each BMI imputation, with results pooled using Rubin’s combining rule.For time of exposure subgroup analysis, a new propensity score was calculated for each of the three timepoints.

eight individuals were excluded from analyses involving different preeclampsia outcomes due to unknown gestational age.

Future Research and Implications

This study provides valuable insights into the potential relationship between antiviral medication use and preeclampsia risk during pregnancy. Further research is needed to confirm these findings and to explore the underlying mechanisms. Understanding these associations can definitely help inform clinical guidelines and improve pregnancy outcomes.

What are your thoughts on the use of antiviral medications during pregnancy? How can we better inform pregnant women about the potential risks and benefits?

Disclaimer: This article provides general information and should not be considered medical advice. Consult with a healthcare professional for personalized guidance and treatment.

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