Reproductive Health Outcomes by Method of Breast Milk Feeding

The purpose of this research is to determine whether there are differences in ovarian suppression between women who are feeding at the breast compared with women who are pumping.

• In the main study, the aim is to compare reproductive health outcomes, including amenorrhea rates, duration of lactation, and resumption of sexual activity, between mothers who are exclusively breastfeeding (i.e. feeding at the breast) and those who are pumping after a term or preterm delivery.
• In the sub-study, the aim is to determine the feasibility and acceptability of using urinary luteinizing hormone (LH) detection kits at home to detect ovulation in exclusively breastmilk feeding women.

Study Overview

• Status: Completed
• Conditions: Breast Feeding; Milk Expression, Breast; Amenorrhea, Postpartum

Detailed Description

Women will be recruited for this study during routine prenatal care. Interested and eligible participants will undergo an informed consent process. After, participants will answer questions regarding demographic information, medical history, obstetric and reproductive history, previous lactation history, and the Infant Feeding Intentions questionnaire.

Participants who are eligible after the second eligibility verification at the time of delivery hospitalization will be enrolled in the study. Enrolled participants will be given breastmilk and infant feeding logs to complete. Study staff will contact participants at 1, 2, 3, 4, 5, and 6 months after delivery to ask about breastmilk feeding practices in the last 24 hours, infant feeding, vaginal bleeding, sexual activity, use of contraceptive methods, and repeat pregnancies. In between the monthly phone calls, study staff will ask participants about the occurrence of vaginal bleeding.

For the sub-study, participants are recruited from the main study. Those who are eligible and interested will undergo an informed consent process. Participants will be given urinary LH detection kits and instructions for use at time of enrollment. Daily urine LH testing will start after 8 weeks postpartum. Participants will also receive monthly diaries to complete in addition to the breastmilk and infant feeding logs in the main study. Study staff will contact participants at 2, 3, 4, 5, and 6 months to review the diary information. If the urine LH test is positive, the participant will undergo a blood draw for serum progesterone levels to confirm ovulation.

The planned enrollment is 394 participants for the main study and 40 participants in the sub-study.

• Study Type: Observational
• Enrollment (Actual): 394

Contacts and Locations

Study Locations

• United States
  • California
    • Sacramento, California, United States, 95817
      • University of California, Davis

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 15 years to 45 years (Child, Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Women who are planning on breastmilk feeding for at least 6 months after delivery of a singleton.

Description

MAIN STUDY

Inclusion Criteria:

• 15 through 45 years old
• planning to feeding her infant exclusively the mother's own milk for at least 6 months after delivery
• receiving prenatal care, plan to deliver, and plan to return to UC Davis for the postpartum visit
• 32 weeks gestation or greater at screening

Exclusion Criteria:

• have a multiple gestation pregnancy
• planning to initiate a hormonal contraceptive method at the postpartum visit

At time of delivery hospitalization, a second eligibility verification will occur and women will be excluded if they:

• initiated a hormonal contraceptive method (specifically intrauterine device, implant, depo provera injections) during the delivery hospitalization
• had a hysterectomy
• did not deliver at UC Davis
• are no longer interested in study participation

SUB-STUDY

Inclusion Criteria:

• enrolled in the main study
• within 8 weeks postpartum after delivering a singleton
• currently amenorrheic
• planning to continue breastmilk feeding for up to 6 months after delivery
• planning to avoid pregnancy in the first 6 months after delivery

Exclusion Criteria:

• less than 18 years old
• have a previous history of irregular or anovulatory cycles
• are using a hormonal method of contraception
• are unwilling to comply with study procedures

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of women who are amenorrheic		6 months postpartum
Proportion of ovulation detected, as measured by serum progesterone levels greater than or equal to 3 ng/mL, in women with a positive urine luteinizing hormone test		6 months postpartum
Proportion of women who would use the urine luteinizing hormone tests again	Survey question with responses of yes, no, unsure/maybe	6 months postpartum

Secondary Outcome Measures

Outcome Measure	Time Frame
Duration of lactation	within 6 months
Time to resumption of sexual activity	within 6 months
Duration of amenorrhea	within 6 months
Time to initiation of another contraceptive method	within 6 months
Proportion of women who meet criteria for lactational amenorrhea method	at 6 months postpartum
Preliminary estimates of contraceptive efficacy of LAM	within 6 months postpartum
Proportion of women feeding at breast, expressing milk, or both at month 1 postpartum	1 month postpartum
Proportion of women feeding at breast, expressing milk, or both at month 2 postpartum	2 months postpartum
Proportion of women feeding at breast, expressing milk, or both at month 3 postpartum	3 months postpartum
Proportion of women feeding at breast, expressing milk, or both at month 4 postpartum	4 months postpartum
Proportion of women feeding at breast, expressing milk, or both at month 5 postpartum	5 months postpartum
Proportion of women feeding at breast, expressing milk, or both at month 6 postpartum	6 months postpartum
Time to ovulation by method of breastmilk feeding (i.e. primarily breastfeeding or primarily pumping)	within 6 months postpartum

Collaborators and Investigators

• Sponsor: University of California, Davis
• Investigators: Principal Investigator: Melissa Chen, MD, UC Davis

Study record dates

Study Major Dates

• Study Start (Actual): June 27, 2018
• Primary Completion (Actual): January 14, 2021
• Study Completion (Actual): January 14, 2021

Study Registration Dates

• First Submitted: May 31, 2018
• First Submitted That Met QC Criteria: June 13, 2018
• First Posted (Actual): June 26, 2018

Study Record Updates

• Last Update Posted (Actual): August 18, 2021
• Last Update Submitted That Met QC Criteria: August 16, 2021
• Last Verified: August 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Menstruation Disturbances; Amenorrhea
• Other Study ID Numbers: 1198922

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No