Preterm delivery and anti-mullerian hormone levels – is there an increased risk for women with polycystic ovary syndrome?

This study investigated if anti-mullerian hormone (AMH) levels are associated with preterm delivery (PTD). They found that higher AMH levels were associated with PTD risk in women with polycystic ovary syndrome (PCOS). 

Polycystic ovary syndrome (PCOS) is caused by cysts on the ovaries. This can lead to irregular periods and a lack of ovulation. PCOS patients can have fertility issues. Assisted reproduction (AR) is more common in PCOS patients. Even after AR, PCOS patients are more likely to have pregnancy complications. One of these is preterm delivery (PTD). 

Antimullerian hormone (AMH) is involved in the release of egg follicles. AMH is a marker of ovarian reserve. Women with PCOS have higher AMH than those with normal fertility. AMH levels remain high in PCOS women during pregnancy. This may have an impact on the developing fetus. It is unclear if AMH levels are associated with PTD in women with PCOS.

This study included 3743 births, 3462 were term deliveries and 281 were PTD. 468 patients had PCOS. AMH levels were measured before embryo transfer (ET). Patients were categorized depending on AMH levels. Two AMH levels were used. These were above 9.75 ng/ml or above 13.66 ng/ml. This represented the 75^th (AMH75) and 90^th (AMH90) percentile, respectively. Patient characteristics were also compared. 

There were slightly more women with PCOS in the PTD group (16%) than in the term delivery group (12.2%). There was a higher rate of male infants with PTD. 

AMH levels were significantly higher in the PTD group than in the term delivery group. AMH levels above 9,75 ng/ml were more common in women that had a PTD. In women with PCOS, the risk of PTD in those with AMH above 9.75 ng/ml was 4-fold higher. The risk of PTD was 2-fold higher in women with AMH levels above 13.66 ng/ml and frozen ET. 

The authors concluded that higher AMH levels were associated with PTD risk in women with PCOS.

This was a retrospective study meaning it looked back in time to analyze data. Some factors may not be accounted for. The number of PCOS patients was relatively small. This study was conducted in a Chinese population with normal BMI. PCOS is commonly associated with high BMI. The findings in this study may not extend to other ethnicities.