Determining the Stage of Menstrual Cycle After Miscarriage
After a miscarriage, the first menstrual period typically occurs within 4-6 weeks, and this first bleeding marks day 1 of the new menstrual cycle. 1, 2
Timing of Menstrual Return After Miscarriage
- The Centers for Disease Control and Prevention (CDC) recognizes that after a spontaneous abortion (miscarriage), combined hormonal contraceptives can be started within the first 7 days, including immediately post-abortion 3
- Approximately 61% of women experience spontaneous resolution of miscarriage within 2 weeks, with rates varying by type of miscarriage (71% for incomplete miscarriage, 53% for empty sac, and 35% for missed miscarriage) 1
- The first menstrual period after miscarriage is considered day 1 of the new menstrual cycle 2
Hormonal Changes After Miscarriage
- After very early pregnancy loss (before 6 weeks gestation), there may be a slower rate of estrogen rise in the subsequent cycle, though this effect is less pronounced than after later miscarriages 2
- Unlike with later miscarriages, very early pregnancy losses do not appear to significantly affect mid-luteal steroid levels in the subsequent cycle 2
- Women who experience recurrent miscarriages and have oligomenorrhea may have low luteal phase estradiol levels, which can affect cycle regularity 4
Determining Cycle Phase After Miscarriage
- If menstrual cycles have returned after miscarriage, and it has been ≤5 days since menstrual bleeding started, the woman is considered to be in the early follicular phase 3
- If it has been >5 days since menstrual bleeding started after miscarriage, the woman may be approaching or in the late follicular/ovulatory phase, requiring additional contraceptive protection if starting hormonal contraceptives 3
- For women who have not yet experienced the return of menstrual cycles after miscarriage, they are considered to be in an amenorrheic state 3
Practical Considerations
- Conception can occur before the first menstrual period following a spontaneous miscarriage, as ovulation may resume as early as 2 weeks after a miscarriage 5
- Conceiving before the first menstrual period after miscarriage is not associated with higher incidence of subsequent miscarriage or adverse outcomes compared to waiting for the first period 5
- For women who wish to track their cycle after miscarriage, the CDC notes that the first day of menstrual bleeding after miscarriage marks day 1 of the new cycle 3
- Subfertile couples who experience a miscarriage have good prospects for spontaneous ongoing pregnancy, with a cumulative spontaneous ongoing pregnancy rate of 70% within 24 months 6
Contraceptive Considerations After Miscarriage
- For women starting contraception after miscarriage, progestin-only pills can be started at any time and require only 2 days of additional contraceptive protection if started >5 days after the onset of menses 3, 7
- Combined hormonal contraceptives can be started within 7 days after miscarriage and require 7 days of additional protection if started >5 days after the onset of menses 3
- For breastfeeding women who have experienced miscarriage and return of menses, progestin-only pills are recommended as they do not affect milk production 7
Remember that after a miscarriage, it's important to monitor for signs of return to normal menstrual cycling, which indicates resumption of ovulatory function and fertility.