Winter, spring, summer or fall: temporal patterns in placenta-mediated pregnancy complications-an exploratory...

Area of Science:

• Obstetrics and Gynecology
• Reproductive Medicine
• Perinatal Health

Background:

• Placenta-mediated pregnancy complications significantly contribute to maternal and neonatal morbidity and mortality in high-income nations.
• Key complications include fetal growth restriction, hypertensive disorders, and preterm birth.

Purpose of the Study:

• To investigate potential seasonal variations in placenta-mediated pregnancy complications.
• Specific focus on small for gestational age, intrauterine growth restriction, preeclampsia, preterm birth, and intrauterine fetal death.

Main Methods:

• A Danish cohort study analyzed 555,459 singleton deliveries from December 2006 to November 2016.
• Statistical process control charts were employed to detect non-random temporal variations in outcomes.
• Risk factors such as BMI, diabetes, IVF, advanced maternal age, primiparity, previous C-section, and smoking were considered.

Main Results:

• A distinct seasonal pattern was observed in hypertensive disorders of pregnancy.
• Pregnancies conceived in spring and summer showed the highest risk for hypertensive disorders.
• No significant seasonality was detected for preterm delivery, small for gestational age, or intrauterine mortality.

Conclusions:

• The risk of hypertensive disorders of pregnancy demonstrates significant seasonal variation, peaking with spring and summer conceptions.
• This study did not find evidence of seasonal variation in other major placenta-mediated complications.