What is the best sleeping position during the 1st trimester of pregnancy?

Best Sleeping Position During First Trimester of Pregnancy

During the first trimester of pregnancy, there is no specific sleeping position that is recommended or restricted, as the concerns about sleeping position primarily apply to later pregnancy stages.

Understanding Sleeping Positions in Pregnancy

• While the American Academy of Pediatrics (AAP) provides extensive guidance on infant sleeping positions to prevent SIDS, there are no equivalent strict guidelines for maternal sleeping positions during early pregnancy 1.

• Research on maternal sleeping positions has primarily focused on the third trimester (after 28 weeks), when the weight of the uterus can potentially compress major blood vessels when lying supine 2, 3.

First Trimester Considerations

• During the first trimester, the uterus is still relatively small and remains within the pelvis, making aortocaval compression less likely compared to later pregnancy stages 4.

• A study of pregnant women's natural sleeping positions found that women beyond 30 weeks gestation naturally tend to adopt side-lying positions (particularly left side) compared to non-pregnant controls, suggesting this is a physiologic adaptation that happens later in pregnancy 4.

Evidence for Later Pregnancy

• Research has shown associations between supine sleeping position in late pregnancy (third trimester) and:

  • Reduced birth weight (approximately 144g lower) 3
  • Increased risk of the baby being small for gestational age 3
  • Potential increased risk of stillbirth (though this remains an area of ongoing research) 5

• A 2019 prospective study found no association between maternal sleep position and adverse pregnancy outcomes when assessed through 30 weeks gestation 2.

Practical Recommendations

• During the first trimester:

  • Sleep in whatever position is most comfortable 4, 2
  • There is no need to actively avoid back sleeping during this early stage 2

• As pregnancy progresses beyond the first trimester:

  • Begin to transition to side-sleeping (particularly left side) as this will become more comfortable naturally and may have benefits in later pregnancy 4, 5
  • By the third trimester, left-side sleeping is generally preferred to optimize blood flow to the uterus 3

Common Pitfalls to Avoid

• Becoming anxious about sleeping position too early in pregnancy when there is no evidence of harm 2
• Using excessive pillows or props that might actually disrupt sleep quality unnecessarily in early pregnancy 4
• Confusing recommendations for infant sleep positioning with maternal sleep positioning (they are entirely different issues) 1