3rd Pregnancy Labor Statistics

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Updated on March 29, 2022

Post-partum pregnancy labor (labor in mothers with previous births) has several similarities with first-time pregnancies, and differences too. Understanding the differences between a first-time and third-time pregnancy isn’t possible without correct information. 

Several factors determine how long a 3rd pregnancy labor period will be. Estimates vary from about 2 hours – 15+ hours and numbers are different among mothers.

However, several relevant stats on 3rd pregnancy labor makes it easy for expectant mothers to better understand their gestation cycle. That’s why this post compiles ten (10) top pregnancy labor statistics for third-time mothers. 

1. Over ten (10) factors determine how long 3rd pregnancy labor will last

Verywell Family, Evidence Based Birth

Prolonged labor is dangerous to both mother and baby, even if the mother has had a successful pregnancy before. The most common factors that determine how long a 3rd pregnancy labor period will last are:

  • A mother’s vaginal birth history
  • Size and shape of the mother’s pelvis
  • Mother’s age
  • Mother’s body mass index (BMI)
  • Position of baby
  • Strength of contractions and timeline
  • Application of drugs for labor induction
  • Significant weight gain during pregnancy
  • Maternal history of post-term births
  • Small fetal measurement by around 10 – 25 weeks
  • Epidural use
  • Stressors late in the third trimester of pregnancy (32 – 36 weeks)

Apart from these factors, other elements might cause a 3rd pregnancy labor to end quickly or last longer. 

2. Post-term pregnancies decrease from 10% – under 3% with timely diagnosis

Evidence Based Birth

A massive observational study involving at least 17,000 women sought to determine the accuracy of ultrasound in locating post-term pregnancies. Pregnancies identified with ultrasound technology instead of LMP helped decrease post-term pregnancies. 

Numbers show that compared to 10% LMP diagnosis of pregnancies, just 2.7% of women experienced post-term pregnancies after ultrasounds. 

3. 3rd pregnancies are likely to complete their gestation cycle in 40 – 41 weeks

Evidence Based Birth

Most 3rd pregnancy labors will begin within 37 – 42 weeks, outside this timeline, births will be considered pre-term or post-term. A combination of factors might make the mother experience pre-term (<37 weeks) or post-term (>42 weeks) labor. 

Research also shows that health challenges might be common in children born over 42 weeks. Post-term babies from mothers with pre-existing health conditions are at even greater risk after birth.  

4. 3rd pregnancies are 4 times likely to end in post-term birth after a previous post-term birth

Evidence Based Birth

Genetics play a massive role in the likelihood of mothers birthing a child after the post-term period. 

A mother who has a history of post-term births is 4.4 times more likely to have another post-term birth in subsequent pregnancies. Mothers are also 3 times as likely to have future post-term births, even if they switch partners. 

There’s also a 2 times chance of having post-term births if your sister or mother has a history of post-term births. 

5. Babies of 3rd pregnancies arrive 5 – 6 days earlier than EDD

Baby Center

Mothers who see changes in their vaginal discharge at the 36 – 37th week are likely to give birth early.  However, mothers with a history of early births have a higher chance of continuing the trend with subsequent deliveries. 

The numbers vary, but babies from 3rd pregnancies might arrive several days earlier than expected. Mothers that have experienced early deliveries in previous pregnancies are even more likely to repeat the trend. 

6. Ultrasound was not used to determine gestational age until the 1970s

Evidence Based Birth, National Library of Medicine

Ultrasound technology was first used medically in 1956. However, it would take about 15 years before ultrasound technology would gain widespread accepted for dating pregnancies. 

The technology became popular among medical practitioners in the 1970s and proved to be more accurate than LMP. 

7. Last menstrual period (LMP) was the most reliable method to determine gestation age pre-1970s

Evidence Based Birth

The last menstrual period was widely accepted as a means to date pregnancies before ultrasound became popular. Many pregnancies were easy to date with the LMP method, but several inaccuracies were common too. 

8. Over 60% of 3rd pregnancies will reach their due date with ± 11 days difference


About 5% of mothers on their third pregnancy will give birth on the expected date of delivery (EDD). 

9. Labor periods of 3rd pregnancies are likely to end faster after 2 – 3 year hiatus 

Baby Center

Mothers who have experienced short labors in their first and second pregnancies are more likely to have a third. Chances of experiencing short labors are even higher in mothers who maintain healthy weight ratings during pregnancy. 

10. Older, weightier mothers are twice as likely to experience longer labors in 3rd pregnancies

 Reuters, Mayo Clinic 

A mother’s age and weight are major factors that determine how long her labor will be in all pregnancies. Mothers who gain much weight during their second, third, and subsequent pregnancies are also twice likely to experience lengthy labors. 

Weightier mothers also run the risk of several complications with each pregnancy.