What are the possible antepartum, intrapartum, and postpartum complications in a 35-year-old primigravida with a body mass index (BMI) of 36.8 m^2?

Complications in a 35-Year-Old Primigravida with BMI 36.8

This patient faces substantially elevated risks across all pregnancy phases due to the combined effects of advanced maternal age (≥35 years) and class II obesity (BMI 36.8), requiring heightened surveillance and likely requiring thromboprophylaxis postpartum.

Antepartum Complications

Metabolic and Hypertensive Disorders

• Gestational diabetes mellitus occurs at significantly higher rates, with obesity (BMI ≥30) recognized as a major risk factor across multiple international guidelines 1
• Pregnancy-induced hypertension/preeclampsia is the most common complication in elderly primigravidas (24.35% vs 6.41% in younger women), and obesity further compounds this risk 2
• Pre-pregnancy obesity increases the risk of excessive gestational weight gain, which independently increases the risk of large-for-gestational-age births 3

Structural and Anatomical Issues

• Uterine fibroids occur more frequently in women ≥35 years (9.61% vs 2.56% in younger primigravidas) 2
• Malpresentation is significantly more common in elderly primigravidas 4, 2
• Obesity substantially impairs ultrasound visualization, reducing detection rates of fetal anomalies on routine anatomic surveys 1

Fetal Complications

• Intrauterine growth restriction (IUGR) occurs at higher rates in elderly primigravidas 4
• Congenital malformations are more frequent (5.12% vs 1.28% in younger women), particularly neural tube defects, cardiovascular anomalies, cleft lip/palate, and limb reduction anomalies in obese patients 2, 1
• Preterm birth risk is elevated, with elderly primigravidas delivering at mean gestational age of 36.06 weeks vs 38.84 weeks in younger women 5

Hemorrhagic Complications

• Antepartum hemorrhage and placental abruption occur at statistically higher rates 4, 1

Other Antepartum Issues

• Hyperemesis gravidarum is more common in elderly primigravidas 4
• Anemia occurs at significantly higher rates 4

Intrapartum Complications

Labor Abnormalities

• Prolonged first stage of labor occurs significantly more frequently in obese primigravidas, requiring increased oxytocin augmentation and higher oxytocin doses 6
• Prolonged second stage of labor is significantly more common 4, 6
• Cephalopelvic disproportion occurs at higher rates in elderly primigravidas 4

Fetal Distress and Operative Delivery

• Fetal distress is statistically more common during labor 4
• Cesarean section rates are dramatically elevated: 53.7% in elderly primigravidas vs younger controls, and 40% in obese primigravidas vs 13% in normal BMI 4, 6
• The combination of age ≥35 and obesity creates a multiplicative effect, with cesarean delivery weighted as +2 risk points when performed in labor 1
• Episiotomy rates reach 94.6% in elderly primigravidas 4

Hemorrhagic Complications

• Primary postpartum hemorrhage occurs at significantly higher rates 4

Postpartum Complications

Infectious Complications

• Postpartum sepsis and wound infection are significantly increased in obese primigravidas 6
• Current systemic infection is recognized as a transient risk factor for VTE across multiple international guidelines 1

Thromboembolic Risk

This patient requires particular attention to VTE prophylaxis:

• Age >35 years carries +1 risk point for VTE 1
• BMI 36.8 (class II obesity, ≥35) carries +2 risk points 1
• If cesarean section occurs (highly likely at 40-53.7% rate), this adds +2 additional points 1
• Total baseline VTE risk score of 3-5 points mandates consideration of thromboprophylaxis with LMWH for at least 10 days postpartum, potentially extending to 6 weeks 7
• The Royal College of O&G, Australian, Irish, Canadian, and American guidelines all identify both age >35 and BMI >30 as preexisting risk factors requiring risk stratification 1

Perineal Trauma

• Perineal tears occur at significantly higher rates in obese women 6

Weight Retention

• Excessive gestational weight gain in women starting pregnancy with elevated BMI leads to substantial postpartum weight retention (0.5-3 kg average, but much higher with excessive gain), increasing long-term obesity and metabolic disease risk 1

Neonatal Complications

Birth Outcomes

• Increased birth weight is significantly more common 6
• Lower Apgar scores at 1 and 5 minutes are statistically significant in elderly primigravidas 5
• Prolonged neonatal intensive care unit stays occur more frequently 6

Mortality

• Perinatal mortality is relatively higher in elderly primigravidas, with 17 stillbirths per group compared to 10 in younger controls 2
• Stillbirth is recognized as an obstetric risk factor for VTE in multiple guidelines 1

Critical Management Considerations

Imaging Modifications

• Anatomic ultrasound surveys should be performed at 20-22 weeks (2 weeks later than standard) due to obesity-related visualization challenges 1
• If incomplete, repeat follow-up ultrasound in 2-4 weeks is indicated 1
• Early transvaginal anatomic evaluation combined with routine transabdominal study may achieve completion rates comparable to non-obese populations 1

Common Pitfalls

• Underestimating cumulative risk: The combination of advanced maternal age and obesity creates multiplicative rather than additive risk 7
• Inadequate VTE prophylaxis: Failing to calculate risk scores and implement appropriate thromboprophylaxis is a critical error given this patient's baseline 3-5 point score 1, 7
• Delayed anatomic surveys: Performing ultrasound at standard 18-20 weeks in obese patients leads to incomplete examinations 1
• Insufficient postpartum surveillance: VTE risk remains elevated for 6 weeks postpartum, with highest risk in first 3 weeks 7