Changes in Oral Contraceptive Hormones After Gastric Bypass Surgery

Study Overview
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Brief Summary
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This study will attempt to determine whether having gastric bypass surgery changes the way that the gut absorbs hormones from birth control pills. It is believed that, because gastric bypass surgery causes malabsorption of nutrients and some medications, the levels of birth control hormones after the surgery will be lower than in women before they have the surgery. The investigators will ask several women to take a pack of birth control pills before having bypass surgery, and then another pack several months after surgery. The investigators will measure hormone levels in the blood. The investigators will also measure outcomes that may tell us how well the birth control pills are working, such as ultrasounds of the uterus and ovaries, and examination of the cervix.

Official Title
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Impact of Gastric Bypass Surgery on the Pharmacokinetics of Oral Contraceptive Hormones

Conditions
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Bariatric Surgery Candidate, Contraception

Intervention / Treatment
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* Drug: ethinyl estradiol-levonorgestrel


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Planning to undergo gastric bypass surgery at our institution willing to take 2 monthly cycles of the oral contraceptive: one cycle before and one after surgery use of Depo-provera within 6 months of enrollment Use of implantable or intrauterine contraception able to attend multiple study visits Exclusion Criteria: Any contraindication to combined hormonal contraceptive use Surgical complications precluding further participation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Gastric bypass COC<br>This is a before-and-after comparison. Women will enroll prior to planned gastric bypass surgery and complete one cycle of oral contraceptive use and evaluation. There will then be no more study procedures/interventions until 3-4 months after surgery. At that time, women will complete the second cycle of OC use and evaluation. Study participation is then complete. Intervention: Ethinyl estradiol-levonorgestrel(EE 20mcg/LNG 150mcg) | Drug: ethinyl estradiol-levonorgestrel<br>* Women will be asked to take a daily ethinyl estradiol-levonorgestrel combined oral contraceptive (COC) for 21 days, beginning 2-3 months pre-operatively, so as to stop at least 30 days before planned surgery date. Then, approximately 3-4 months after surgery, they will again be asked to take a daily pill for 21 days. During these pill cycles, we will collect serum samples and perform ultrasound and cervical mucus assessments on a twice-weekly basis, culminating in an inpatient stay of up to 48 hours in order to obtain more frequent sampling at the end of the pill pack.<br>* Other names: EE-LNG oral contraceptive;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum hormone levels of Ethinyl estradiol and levonorgestrel, as assessed by area under the curve (AUC) |  | twice weekly x 4 weeks, at 2 separate months: 1 pre-op and one 3-4 months postoperative. Thus, total duration of participation in study will be approximately 7-8 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endometrial thickness on transvaginal ultrasound |  | twice weekly x 4 weeks, at 2 separate months: 1 pre-op and one 3-4 months postoperative. Thus, total duration of participation in study will be approximately 7-8 months | 
| Serum levels of FSH, LH, E and P | Serum levels of Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), estradiol (E) and progesterone (P) | twice weekly x 4 weeks, at 2 separate months: 1 pre-op and one 3-4 months postoperative. Thus, total duration of participation in study will be approximately 7-8 months | 
| Cervical mucus score | We will assess cervical mucus favorability according to standard criteria. | twice weekly x 4 weeks, at 2 separate months: 1 pre-op and one 3-4 months postoperative. Thus, total duration of participation in study will be approximately 7-8 months | 
| Presence of ovarian follicles on transvaginal ultrasound | We will assess for and measure ovarian follicles with maximum diameter 10mm or greater | twice weekly x 4 weeks, at 2 separate months: 1 pre-op and one 3-4 months postoperative. Thus, total duration of participation in study will be approximately 7-8 months |