A new study has suggested that women may have to wait 8 months for fertility to return after ending their use of injectable contraceptives. The findings of the study are published in The BMJ.
In women after the use of different contraceptive methods, the US and Danish researchers have measured the delay in the return of fertility.
They discovered that the time until fertility returned varied depending on which contraceptive method was used. The return to fertility was not associated with how long the woman had been using contraceptives.
To round out the picture, a team of Boston University School of Public Health researchers led by Jennifer Yland, in collaboration with Aarhus University in Denmark, set out to evaluate the link between pre-pregnancy use of various contraceptive methods and the subsequent probability of becoming pregnant (fecundability).
For their study, the researchers gathered data from three studies that involved nearly 18,000 women from Denmark and North America who planned pregnancies between 2007 and 2019.
At the start of the study, the women reported their contraceptive histories and personal, medical, and lifestyle information.
For up to 12 months or until they reported they had become pregnant follow-up questionnaires were sent to the study participantsmore than 80% of participants completed at least one follow-up questionnaire.
Overall, there were 10,729 pregnancies recorded in these women during 66,759 menstrual cycles of observation. Approximately 56% of women conceived within 6 cycles of follow-up, and 77% within 12 cycles.
Contraceptive Methods Used by the Study Participants
The most commonly reported method of contraception was oral contraceptives (38%), followed by barrier methods such as condoms, diaphragm and sponge (31%), and natural methods such as withdrawal and avoiding sex when fertile (15%).
Approximately 13% of women used long-acting reversible contraceptive methods; the most frequently used of these were IUDs - 8% of women used the hormonal IUD and 4% of women used the copper IUD as their last method of contraception.
Women experienced short-term delays in a return to fertility if they had recently stopped using oral contraceptives, the contraceptive ring, and some long-acting reversible contraceptive methods.
Women who used injectable contraceptives had the longest delay in return of normal fertility (five to eight cycles), followed by users of patch contraceptives (four cycles), users of oral contraceptives and vaginal rings (three cycles), and users of hormonal and copper intrauterine devices and implant contraceptives (two cycles).
Study limitations include - data on the date of the last injection for women who used injectable contraceptives was lacking.
The authors noted that: "Our results, although imprecise, indicate little or no lasting effect of long term use of these methods on fecundability .... these findings might inform clinical recommendations on contraceptive decision making."
- In 2019, about 22% of reproductive-aged women used hormonal contraception.
- Male condoms and oral contraceptives are the most commonly used methods in North America and Europe.
- Long-acting reversible contraceptive (LARC) methods such as intrauterine devices (IUDs), implants, patches and injectable contraceptives have become increasingly popular globally.