Does a partially septate uterus increase the risk of pregnancy complications?

Pregnancy Complications Associated with Partially Septate Uterus

A partially septate uterus is associated with increased risks of pregnancy complications, including miscarriage, preterm birth, and fetal malpresentation, though evidence regarding treatment benefits remains mixed.

Understanding the Risk

Septate uterus is one of the most common uterine anomalies, with prevalence estimated at 0.2-2.3% in women of reproductive age 1. This congenital malformation can impact pregnancy outcomes in several ways:

Documented Risks:

• Miscarriage: Women with an untreated septate uterus have higher rates of pregnancy loss. In one prospective study of women with incidentally diagnosed septate uterus at first trimester scan, only 33.3% of pregnancies progressed beyond the second trimester, with 13 early miscarriages (≤13 weeks) and 3 late miscarriages (14-22 weeks) 2.

• Preterm Birth: Nulliparous women with untreated septate uterus have significantly higher rates of preterm birth compared to those who underwent septum resection (31.6% vs 4.5%) 3.

• Fetal Malpresentation: Higher rates of malpresentation have been observed, though evidence is mixed. One study showed malpresentation in 34.6% of women with untreated septate uterus compared to 19.1% in those who underwent resection 1.

Evidence Quality and Conflicts

The evidence regarding septate uterus and pregnancy complications has limitations:

1. Limited High-Quality Studies: Most evidence comes from retrospective cohort studies rather than randomized controlled trials 4.

2. Conflicting Results: While some studies show improved outcomes after septum resection, a large international cohort study found no significant improvement in live birth rates after septum resection (53.0% vs 71.7% with expectant management) 1.

3. Potential Confounding Factors: Women with septate uterus may have other factors affecting pregnancy outcomes that aren't always controlled for in studies.

Management Considerations

The American Society for Reproductive Medicine (ASRM) guideline indicates that while septate uterus has been associated with increased risk of miscarriage, premature delivery, and malpresentation, there is insufficient evidence that it directly causes infertility 5.

For women with a history of pregnancy loss:

• Several studies suggest that treating a uterine septum may improve live-birth rates in women with prior pregnancy loss or recurrent pregnancy loss 5
• In nulliparous women specifically, hysteroscopic septum resection has been associated with later gestational ages at delivery (39.1 vs 37 weeks) and decreased preterm birth rates 3

For women without prior pregnancy complications:

• The benefits of prophylactic septum resection are less clear
• ASRM states it may be reasonable to consider septum incision after counseling regarding potential risks and benefits 5

Important Caveats

1. Surgical Risks: Hysteroscopic septum resection carries risks including uterine perforation, bleeding, infection, and potential for uterine rupture in subsequent pregnancies.

2. Cesarean Delivery: Some evidence suggests higher cesarean delivery rates in women who have undergone septum resection 3.

3. Ongoing Research: Two randomized controlled trials were underway as of 2017 to better evaluate the benefits of septum resection 4.

Conclusion

Women with a partially septate uterus should be counseled about the increased risks of pregnancy complications, particularly miscarriage and preterm birth. While septum resection is commonly performed, the decision should be based on individual reproductive history, with stronger consideration for those with prior pregnancy losses or adverse outcomes.