Does dialysis (renal replacement therapy) affect fertility and pregnancy?

Dialysis Significantly Reduces Fertility and Pregnancy Success Rates

Women on dialysis have significantly reduced fertility and face higher risks of pregnancy complications, but intensive dialysis (>36 hours weekly) can improve pregnancy outcomes with live birth rates reaching 85% compared to 48% with conventional dialysis regimens. 1

Impact of Dialysis on Fertility

• Fertility is markedly reduced in women with end-stage kidney disease (ESKD) on dialysis:
  • Pregnancy occurs in only 1-7% of women of childbearing age on chronic dialysis 2
  • Women should not assume they are infertile and should use contraception if pregnancy is not desired 3

Pregnancy Outcomes on Dialysis

Success Rates

• Overall pregnancy success rate in dialysis patients is approximately 50% 3, 4
• Strong dose-response relationship between dialysis intensity and pregnancy outcomes:
  • 48% live birth rate with ≤20 hours/week dialysis
  • 75% live birth rate with 30 hours/week dialysis
  • 85% live birth rate with >36 hours/week dialysis 1

Maternal and Fetal Complications

• Maternal complications:

  • Hypertension (most significant risk)
  • Volume overload requiring increased dialysis
  • Anemia requiring higher doses of erythropoietin
  • Electrolyte imbalances
  • Risk of permanent worsening of renal function 1

• Fetal complications:

  • High rates of prematurity (>80% of live births) 4
  • Low birth weight
  • Increased risk of miscarriage and stillbirth
  • Shorter gestational age (mean 27 weeks with conventional dialysis vs. 36 weeks with intensive dialysis) 1

Management of Pregnant Women on Dialysis

Dialysis Prescription

• Intensive hemodialysis is recommended:
  • 6 nights per week
  • Total weekly time of 36-48 hours 1
  • Target spKt/V of 1.4 per session for thrice-weekly regimens 1

Blood Pressure Management

• Aggressive blood pressure control is essential 3
• Recommended medications:
  • Methyldopa (750 mg to 4 g daily in 3-4 divided doses)
  • Labetalol (100 mg twice daily up to 2400 mg daily)
  • Nifedipine (avoid sublingual/IV administration)
  • Clonidine (0.1-0.3 mg daily in divided doses) 1
  • AVOID ACE inhibitors and ARBs as they cause renal dysgenesis in the fetus 1

Laboratory Monitoring

• Target serum bicarbonate: 18-20 mEq/L 4
• Careful monitoring of phosphorus and potassium (risk of excessive removal) 4
• Increased supplementation of water-soluble vitamins, particularly folate 4
• Higher doses of erythropoietin to meet increased red cell production demands 4

Multidisciplinary Approach

• Close collaboration required between:
  • Nephrologist
  • Dialysis staff
  • Obstetrician
  • Neonatologist 2
• Weekly home blood pressure monitoring
• Monthly urinalysis
• Prompt treatment of bacteriuria, even if asymptomatic 5

Prevention of Complications

• Low-dose aspirin from week 12 to week 36 for preeclampsia prophylaxis 5
• Indomethacin for treatment of premature labor 3
• Steroids for 48 hours to accelerate lung maturation if gestation is <34 weeks 1
• Regular monitoring for signs of preeclampsia 5

Key Pitfalls to Avoid

1. Inadequate dialysis intensity: Conventional dialysis regimens lead to significantly worse outcomes compared to intensive regimens
2. Poor blood pressure control: Hypertension is the greatest danger to both mother and fetus
3. Inappropriate medication use: ACE inhibitors and ARBs must be discontinued due to fetal toxicity
4. Electrolyte imbalances: Excessive removal of phosphorus and potassium during intensive dialysis
5. Delayed recognition of premature labor: The key to improving outcomes is decreasing premature labor and premature rupture of membranes

While pregnancy outcomes for women on dialysis have improved over time, these remain high-risk pregnancies requiring intensive monitoring and management to maximize the chances of successful outcomes.