Does Delivery Mode Affect the Ovarian Reserve?

Vaginal versus cesarean deliveries were compared in terms of ovarian reserve.

Key Points

Highlights:

• Cesarean delivery is not associated with a decrease in ovarian reserve, as estimated by anti-mullerian hormone levels.
• Anti-mullerian hormone plasma levels increased two-fold regardless of the delivery model in the postpartum period. 

Importance:

• Age should be the basic parameter influencing fertility and anti-mullerian hormone levels in women.

What's done here:

• This is a prospective, non-randomized cohort study at a tertiary clinic in Israel.
• The aim is to assess the change of ovarian reserve in women who are delivered by the cesarian section (n=125) and to compare it to vaginal delivery (n=139).
• The ovarian reserve changes were evaluated by measuring plasma anti-mullerian hormone levels of the patients in their third trimester, and 3 months after the delivery.

Key results:

• Anti-mullerian hormone levels after vaginal delivery and cesarian delivery did not show any statistical difference.
• Anti-mullerian hormone plasma levels increased two-fold after 3 months in both groups.
• Regression analyses revealed that age was the only parameter associated with the change of Anti-mullerian hormone levels before and after the delivery. This change was smaller when women were older.

Limitations:

• Anti-mullerian hormone levels tend to decline by age and reflect a decrease in ovarian reserve. For this reason, age differences between the two group is an important limitation of the study. 
• The non-random assignment of patients is another limitation.

Lay Summary

Mohr-Sasson et al. from Sheba Medical Center, Israel,  performed a prospective case-control study to assess whether ovarian reserve decreases after cesarian delivery. The study included only women with singleton pregnancies and the change in ovarian reserve after vaginal or cesarian deliveries was estimated by anti-mullerian hormone plasma levels, before one week and after 3 months from the delivery.

The ovarian reserve is the reproductive potential of ovaries and the number and quality of eggs. When diminishes, it means a lower count or quality of the remaining eggs. Ovarian reserve may be diminished in women with endometriosis due to previous laparoscopies, hence the selection of the mode of delivery should be important for endometriosis patients.

Plasma levels of Anti-Mullerian Hormone before and after the deliveries were significantly different in both groups and was more than doubled. Women in the cesarian section group were significantly older, had higher BMI, and had more premature deliveries when compared to women with vaginal deliveries. When statistical analyses were made based on maternal age, gestational age at the delivery, and delta hemoglobin levels in order to assess the further association between the two groups, maternal age was found the only independent factor associated with the changes in AMH levels before and after delivery.

The authors anticipated that the suppression of Anti-Mullerian Hormone plasma levels during pregnancy should be due to increased progesterone production. Judging by this interpretation, more than a two-fold increase of plasma AMH levels after the delivery can be considered as expected. The paper is recently published in "Reproductive Sciences".

Research Source: https://pubmed.ncbi.nlm.nih.gov/34472035/