The effect of various contraceptive hormonal therapies in women with normal and diabetic oral glucose tolerance test

Steroidal contraceptives: effect on carbohydrate metabolism in women without diabetes mellitus

BACKGROUND

Many hormonal contraceptives have been associated with changes in carbohydrate metabolism. Alterations may include decreased glucose tolerance and increased insulin resistance, which are risk factors for Type 2 diabetes mellitus and cardiovascular disease. These issues have been raised primarily with contraceptives containing estrogen.

OBJECTIVES

To evaluate the effect of hormonal contraceptives on carbohydrate metabolism in healthy women and those at risk for diabetes due to overweight.

SEARCH METHODS

In April 2014, we searched the computerized databases MEDLINE, POPLINE, CENTRAL, and LILACS for studies of hormonal contraceptives and carbohydrate metabolism. We also searched for clinical trials in ClinicalTrials.gov and ICTRP. The initial search also included EMBASE.

SELECTION CRITERIA

All randomized controlled trials were considered if they examined carbohydrate metabolism in women without diabetes who used hormonal contraceptives for contraception. Comparisons could be a placebo, a non-hormonal contraceptive, or another hormonal contraceptive that differed in drug, dosage, or regimen. Interventions included at least three cycles. Outcomes included glucose and insulin measures.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts identified during the literature searches. The data were extracted and entered into RevMan. We wrote to researchers for missing data. For continuous variables, the mean difference (MD) was computed with 95% confidence interval (CI) using a fixed-effect model. For dichotomous outcomes, the Peto odds ratio with 95% CI was calculated.

MAIN RESULTS

We found 31 trials that met the inclusion criteria. No new trials were eligible in 2014. Twenty-one trials compared combined oral contraceptives (COCs); others examined different COC regimens, progestin-only pills, injectables, a vaginal ring, and implants. None included a placebo. Of 34 comparisons, eight had any notable difference between the study groups in an outcome.Twelve trials studied desogestrel-containing COCs, and the few differences from levonorgestrel COCs were inconsistent. A meta-analysis of two studies showed the desogestrel group had a higher mean fasting glucose (MD 0.20; 95% CI 0.00 to 0.41). Where data could not be combined, single studies showed lower mean fasting glucose (MD -0.40; 95% CI -0.72 to -0.08) and higher means for two-hour glucose response (MD 1.08; 95% CI 0.45 to 1.71) and insulin area under the curve (AUC) (MD 20.30; 95% CI 4.24 to 36.36).Three trials examined the etonogestrel vaginal ring and one examined an etonogestrel implant. One trial showed the ring group had lower mean AUC insulin than the levonorgestrel-COC group (MD -204.51; 95% CI -389.64 to -19.38).Of eight trials of norethisterone preparations, five compared COCs and three compared injectables. In a COC trial, a norethisterone group had smaller mean change in glucose two-hour response than a levonorgestrel-COC group (MD -0.30; 95% CI -0.54 to -0.06). In an injectable study, a group using depot medroxyprogesterone acetate had higher means than the group using norethisterone enanthate for fasting glucose (MD 10.05; 95% CI 3.16 to 16.94), glucose two-hour response (MD 17.00; 95% CI 5.67 to 28.33), and fasting insulin (MD 3.40; 95% CI 2.07 to 4.73).Among five recent trials, two examined newer COCs with different estrogen types. One showed the group with nomegestrel acetate plus 17β-estradiol had lower means than the levonorgestrel group for incremental AUC glucose (MD -1.43; 95% CI -2.55 to -0.31) and glycosylated hemoglobin (HbA1c) (MD -0.10; 95% CI -0.18 to -0.02). Two trials compared extended versus conventional (cyclic) regimens. With a dienogest COC, an extended-use group had greater mean change in AUC glucose (MD 82.00; 95% CI 10.72 to 153.28). In a small trial using two levonorgestrel COCs, the lower-dose group showed smaller mean change in fasting glucose (MD -3.00; 95% CI -5.89 to -0.11), but the obese and normal weight women did not differ significantly.

AUTHORS' CONCLUSIONS

Current evidence suggests no major differences in carbohydrate metabolism between different hormonal contraceptives in women without diabetes. We cannot make strong statements due to having few studies that compared the same types of contraceptives. Many trials had small numbers of participants and some had large losses. Many of the earlier studies had limited reporting of methods.We still know very little about women at risk for metabolic problems due to being overweight. More than half of the trials had weight restrictions as inclusion criteria. Only one small trial stratified the groups by body mass index (obese versus normal).

Hormonal versus non-hormonal contraceptives in women with diabetes mellitus type 1 and 2

BACKGROUND

Adequate contraceptive advice is important in both women with diabetes mellitus type 1 and type 2 to reduce the risk of maternal and infant morbidity and mortality in unplanned pregnancies. A wide variety of contraceptives are available for these women. However, hormonal contraceptives might influence carbohydrate and lipid metabolism and increase micro- and macrovascular complications, so caution in selecting a contraceptive method is required.

OBJECTIVES

To investigate whether progestogen-only, combined estrogen and progestogen or non-hormonal contraceptives differ in terms of effectiveness in preventing pregnancy, in their side effects on carbohydrate and lipid metabolism, and in long-term complications such as micro- and macrovascular disease when used in women with diabetes mellitus.

SEARCH METHODS

The search was performed in CENTRAL, MEDLINE, EMBASE, POPLINE, CINAHL, WorldCat, ECO, ArticleFirst, the Science Citation Index, the British Library Inside, and reference lists of relevant articles. The last search was performed in January 2013. In addition, experts in the field and pharmaceutical companies marketing contraceptives were contacted to identify published, unpublished or ongoing studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that studied women with diabetes mellitus comparing: 1. hormonal versus non-hormonal contraceptives; 2. progestogen-only versus estrogen and progestogen contraceptives; 3. contraceptives containing < 50 µg estrogen versus contraceptives containing ≥ 50 µg estrogen; and 4. contraceptives containing first-, second- and third-generation progestogens, drospirenone and cyproterone acetate. The principal outcomes were contraceptive effectiveness, diabetes control, lipid metabolism and micro- and macrovascular complications.

DATA COLLECTION AND ANALYSIS

Two investigators evaluated the titles and abstracts identified from the literature search. Quality assessment was performed independently with discrepancies resolved by discussion or consulting a third review author. Because the trials differed in studied contraceptives, participant characteristics and methodological quality, we could not combine the data in a meta-analysis. The trials were therefore examined on an individual basis and narrative summaries were provided.

MAIN RESULTS

Four randomised controlled trials were included. No unintended pregnancies were reported during the study periods. Only one trial was of good methodological quality. It compared the influence of a levonorgestrel-releasing intrauterine device (IUD) versus a copper IUD on carbohydrate metabolism in women with type 1 diabetes mellitus. No significant difference was found between the two groups. The other three trials were of limited methodological quality. Two compared progestogen-only pills with different estrogen and progestogen combinations, and one also included the levonorgestrel-releasing IUD and copper IUD. The trials reported that blood glucose levels remained stable during treatment with most regimens. Only high-dose combined oral contraceptives and 30 µg ethinylestradiol + 75 µg gestodene were identified as slightly impairing glucose homeostasis. The three studies found conflicting results regarding lipid metabolism. Some combined oral contraceptives appeared to have a minor adverse effect while others appeared to slightly improve lipid metabolism. The copper IUD and progestogen-only oral contraceptives also slightly improved lipid metabolism and no influence was seen while using the levonorgestel-releasing IUD. Only one study reported on micro- and macrovascular complications. It observed no signs or symptoms of thromboembolic incidents or visual disturbances, however study duration was short. Only minor adverse effects were reported in two studies.

AUTHORS' CONCLUSIONS

The four included randomised controlled trials in this systematic review provided insufficient evidence to assess whether progestogen-only and combined contraceptives differ from non-hormonal contraceptives in diabetes control, lipid metabolism and complications. Three of the four studies were of limited methodological quality, sponsored by pharmaceutical companies and described surrogate outcomes. Ideally, an adequately reported, high-quality randomised controlled trial analysing both intermediate outcomes (that is glucose and lipid metabolism) and true clinical endpoints (micro- and macrovascular disease) in users of combined, progestogen-only and non-hormonal contraceptives should be conducted. However, due to the low incidence of micro- and macrovascular disease and accordingly the large sample size and long follow-up period needed to observe differences in risk, a randomised controlled trial might not be the ideal design.

Steroidal contraceptives: effect on carbohydrate metabolism in women without diabetes mellitus

BACKGROUND

Many hormonal contraceptives have been associated with changes in carbohydrate metabolism. Alterations may include decreased glucose tolerance and increased insulin resistance, which are risk factors for Type 2 diabetes mellitus and cardiovascular disease. These issues have been raised primarily with contraceptives containing estrogen.

OBJECTIVES

To evaluate the effect of hormonal contraceptives on carbohydrate metabolism in healthy women and those at risk for diabetes due to overweight.

SEARCH METHODS

In February 2012, we searched the computerized databases MEDLINE, POPLINE, CENTRAL, and LILACS for studies of hormonal contraceptives and carbohydrate metabolism. We also searched for clinical trials in ClinicalTrials.gov and ICTRP. Previous searches also included EMBASE.

SELECTION CRITERIA

All randomized controlled trials were considered if they examined carbohydrate metabolism in women without diabetes who used hormonal contraceptives for contraception. Comparisons could be a placebo, a non-hormonal contraceptive, or another hormonal contraceptive that differed in drug, dosage, or regimen. Interventions included at least three cycles. Outcomes included glucose and insulin measures.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts identified during the literature searches. The data were extracted and entered into RevMan. We wrote to researchers for missing data. For continuous variables, the mean difference (MD) was computed with 95% confidence interval (CI) using a fixed-effect model. For dichotomous outcomes, the Peto odds ratio with 95% CI was calculated.

MAIN RESULTS

We found 31 trials that met the inclusion criteria. Twenty-one trials compared combined oral contraceptives (COCs); others examined different COC regimens, progestin-only pills, injectables, a vaginal ring, and implants. None included a placebo. Of 34 comparisons, eight had any notable difference between the study groups in an outcome.Twelve trials studied desogestrel-containing COCs, and the few differences from levonorgestrel COCs were inconsistent. A meta-analysis of two studies showed the desogestrel group had a higher mean fasting glucose (MD 0.20; 95% CI 0.00 to 0.41). Where data could not be combined, single studies showed lower mean fasting glucose (MD -0.40; 95% CI -0.72 to -0.08) and higher means for two-hour glucose response (MD 1.08; 95% CI 0.45 to 1.71) and insulin area under the curve (AUC) (MD 20.30; 95% CI 4.24 to 36.36).Three trials examined the etonogestrel vaginal ring and one examined an etonogestrel implant. One trial showed the ring group had lower mean AUC insulin than the levonorgestrel-COC group (MD -204.51; 95% CI -389.64 to -19.38).Of eight trials of norethisterone preparations, five compared COCs and three compared injectables. In a COC trial, a norethisterone group had smaller mean change in glucose two-hour response than a levonorgestrel-COC group (MD -0.30; 95% CI -0.54 to -0.06). In an injectable study, a group using depot medroxyprogesterone acetate had higher means than the group using norethisterone enanthate for fasting glucose (MD 10.05; 95% CI 3.16 to 16.94), glucose two-hour response (MD 17.00; 95% CI 5.67 to 28.33), and fasting insulin (MD 3.40; 95% CI 2.07 to 4.73).Among five recent trials, two examined newer COCs with different estrogen types. One showed the group with nomegestrel acetate plus 17β-estradiol had lower means than the levonorgestrel group for incremental AUC glucose (MD -1.43; 95% CI -2.55 to -0.31) and glycosylated hemoglobin (HbA1c) (MD -0.10; 95% CI -0.18 to -0.02). Two trials compared extended versus conventional (cyclic) regimens. With a dienogest COC, an extended-use group had greater mean change in AUC glucose (MD 82.00; 95% CI 10.72 to 153.28). In a small trial using two levonorgestrel COCs, the lower-dose group showed smaller mean change in fasting glucose (MD -3.00; 95% CI -5.89 to -0.11), but the obese and normal weight women did not differ significantly.

AUTHORS' CONCLUSIONS

Current evidence suggests no major differences in carbohydrate metabolism between different hormonal contraceptives in women without diabetes. We cannot make strong statements due to having few studies that compared the same types of contraceptives. Many trials had small numbers of participants and some had large losses. Many of the earlier studies had limited reporting of methods.We still know very little about women at risk for metabolic problems due to being overweight. More than half of the trials had weight restrictions as inclusion criteria. Only one small trial stratified the groups by body mass index (obese versus normal).

Steroidal contraceptives: effect on carbohydrate metabolism in women without diabetes mellitus

BACKGROUND

Many hormonal contraceptives have been associated with changes in carbohydrate metabolism. Alterations may include decreased glucose tolerance and increased insulin resistance, which are risk factors for Type 2 diabetes mellitus and cardiovascular disease. These issues have been raised with progestin-only contraceptives as well as contraceptives containing estrogen. Such potential effects could influence recommendations for, and use of, these widely used and effective contraceptives.

OBJECTIVES

To evaluate the effect of hormonal contraceptives on carbohydrate metabolism in healthy women and those at risk for diabetes due to overweight.

SEARCH STRATEGY

We searched the computerized databases MEDLINE, POPLINE, CENTRAL, EMBASE, and LILACS for studies of hormonal contraceptives and carbohydrate metabolism. We also searched for clinical trials in ClinicalTrials.gov and ICTRP. We wrote to investigators for information about other published or unpublished trials.

SELECTION CRITERIA

All randomized controlled trials were considered if they examined carbohydrate metabolism in women without diabetes who used hormonal contraceptives for contraception. Interventions could include comparisons of a hormonal contraceptive with a placebo, a non-hormonal contraceptive, or another hormonal contraceptive that differed in drug, dosage, or regimen. Interventions included at least three cycles. Outcomes included glucose and insulin levels, which were generally reported as fasting value or response to an oral glucose tolerance test.

DATA COLLECTION AND ANALYSIS

We assessed for inclusion all titles and abstracts identified during the literature searches with no language limitations. The data were abstracted and entered into RevMan. Studies were examined for methodological quality. For continuous variables, the mean difference was computed with 95% confidence interval (CI) using a fixed-effect model. For dichotomous outcomes, the Peto odds ratio with 95% CI was calculated.

MAIN RESULTS

We found 43 trials that met the inclusion criteria. No study stratified by body weight (normal-weight versus overweight women). Results for desogestrel were often favorable regarding carbohydrate metabolism but inconsistent overall. Glucose and insulin means were more favorable for norethisterone in studies of progestin-only contraceptives. For other progestins, little or no difference was noted across trials.

AUTHORS' CONCLUSIONS

Current evidence suggests that hormonal contraceptives have limited effect on carbohydrate metabolism in women without diabetes. Strong statements cannot be made, though, due to having few studies that compared any particular types of contraceptives. Many trials had small numbers of participants and some had large losses. Many studies had poor reporting of methods. No information was available regarding the effects among women who were overweight.

Steroidal contraceptives: effect on carbohydrate metabolism in women without diabetes mellitus

BACKGROUND

Many hormonal contraceptives have been associated with changes in carbohydrate metabolism. Alterations may include decreased glucose tolerance and increased insulin resistance, which are risk factors for Type 2 diabetes mellitus and cardiovascular disease. These issues have been raised with progestin-only contraceptives as well as contraceptives containing estrogen. Such potential effects could influence recommendations for, and use of, these widely used and effective contraceptives.

OBJECTIVES

To evaluate the effect of hormonal contraceptives on carbohydrate metabolism in healthy women and those at risk for diabetes due to overweight.

SEARCH STRATEGY

We searched the computerized databases MEDLINE, POPLINE, CENTRAL, EMBASE, and LILACS for studies of hormonal contraceptives and carbohydrate metabolism. The latest search was conducted in March 2006. We wrote to investigators for information about other published or unpublished trials.

SELECTION CRITERIA

All randomized controlled trials (RCTs) were considered if they examined carbohydrate metabolism in women without diabetes who used hormonal contraceptives for contraception. Interventions included comparisons of a hormonal contraceptive with a placebo, a non-hormonal contraceptive, or another hormonal contraceptive that differed in drug, dosage, or regimen. Interventions included at least three cycles. Outcomes included glucose and insulin levels, which were generally reported as fasting value or response to an oral glucose tolerance test.

DATA COLLECTION AND ANALYSIS

We assessed for inclusion all titles and abstracts identified during the literature searches with no language limitations. The data were abstracted and the information was entered into RevMan. Studies were examined for methodological quality. For continuous variables, the weighted mean difference was computed with 95% confidence interval (CI) using a fixed-effect model. For dichotomous outcomes, the Peto odds ratio (OR) with 95% CI was calculated.

MAIN RESULTS

A total of 39 trials met the inclusion criteria. No study stratified by body weight (normal-weight versus overweight women). Results for desogestrel were often favorable regarding carbohydrate metabolism but inconsistent overall. Glucose and insulin means were more favorable for norethisterone in studies of progestin-only contraceptives. For other progestins, little or no difference was noted across trials.

AUTHORS' CONCLUSIONS

Current evidence suggests that hormonal contraceptives have limited effect on carbohydrate metabolism in women without diabetes. Strong statements cannot be made, though, due to having few studies that compared any particular types of contraceptives. Many trials had small numbers of participants and some had large losses to follow up. Most studies had poor reporting of methods. No information was available regarding the effects among women who were overweight.

Hormonal versus non-hormonal contraceptives in women with diabetes mellitus type 1 and 2

BACKGROUND

Adequate contraceptive advice is important in women with diabetes mellitus type 1 and 2 to reduce the risk of maternal and infant morbidity and mortality in unplanned pregnancies. A wide variety of contraceptives are available for these women. However hormonal contraceptives might influence carbohydrate and lipid metabolism and increase micro- and macrovascular complications. So caution in selecting a contraceptive method is required.

OBJECTIVES

To investigate whether progestogen-only, combined estrogen/progestogen or non-hormonal contraceptives differ in terms of effectiveness in preventing pregnancy, in their side effects on carbohydrate and lipid metabolism and in long-term complications such as micro- and macrovascular disease, when used in women with diabetes mellitus.

SEARCH STRATEGY

The search was performed in MEDLINE, EMBASE, CENTRAL/CCTR, POPLINE, CINAHL, WorldCat, ECO, ArticleFirst, the Science Citation Index, the British Library Inside, and reference lists of relevant articles. Last search was performed in May 2005. In addition, experts in the field and pharmaceutical companies marketing contraceptives were contacted to identify published, unpublished or ongoing studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that studied women with diabetes mellitus comparing: 1. hormonal versus non-hormonal contraceptives. 2. progestogen-only versus estrogen/progestogen contraceptives. 3. contraceptives containing <50 microg estrogen versus contraceptives containing > or = 50 microg estrogen. 4. contraceptives containing 'first'-, 'second'- and 'third'-generation progestogens, drospirenone and cyproterone acetate. Principal outcomes were contraceptive effectiveness, diabetes control, lipid metabolism and micro- and macrovascular complications.

DATA COLLECTION AND ANALYSIS

Two investigators evaluated the titles and abstracts from the literature search. Quality assessment was performed independently with discrepancies resolved by discussion or consulting a third reviewer. Because the trials differed in studied contraceptives, participant characteristics and methodological quality, we could not combine the data in a meta-analysis. The trials were therefore examined on an individual basis and narrative summaries were provided.

MAIN RESULTS

Three randomised controlled trials were included. Only one was of good methodological quality. It compared the influence of levonorgestrel-releasing IUD versus copper-IUD on carbohydrate metabolism in women with type 1 diabetes mellitus. No difference was found in daily insulin requirement, glycosylated hemoglobin (HbA1c) or fasting blood sugar after twelve months. The other two trials were of limited methodological quality. Both compared progestogen-only pills with different estrogen/progestogen combinations. The trials reported blood glucose levels to remain stable during treatment with most regimens. Only high-dose combined oral contraceptives were found to slightly impair glucose homeostasis. Combined oral contraceptives also appeared to have a minor adverse effect on lipid metabolism whereas progestogen-only contraceptives slightly improved lipid-metabolism. Only one study reported on micro- and macrovascular complications. No signs or symptoms of thromboembolic incidents or visual disturbances were observed. However study duration was short. Minor adverse effects were reported in one study. The trial found progestogen-only pills to cause more bleeding irregularities when compared with combined oral contraceptives. Unintended pregnancies were not observed during any of the studies.

AUTHORS' CONCLUSIONS

The three included randomised controlled trials in this systematic review provided insufficient evidence to assess whether progestogen-only and combined contraceptives differ from non-hormonal contraceptives in diabetes control, lipid metabolism and complications. Two of the three studies were of limited methodological quality, sponsored by pharmaceutical companies and described surrogate outcomes. Ideally, an adequately reported, high-quality randomised controlled trial analysing both intermediate outcomes (i.e. glucose and lipid metabolism) and true clinical endpoints (micro- and macrovascular disease) in users of combined, progestogen-only and non-hormonal contraceptives should be conducted. However, due to the low incidence of micro- and macrovascular disease and accordingly the large sample size and follow-up period needed to observe differences in risk, a randomised controlled trial might not be the ideal design.

Oral contraceptives, insulin resistance and ischemic vascular disease

From a large prospective study on diabetes risks, 1112 professionally active, non-menopausal, non-pregnant, healthy women were cross-sectionally analysed according to their use of oral contraception. After adjustment for age, weight and diabetes risk factors, those taking the pill, compared to those who did not, had significantly higher fasting serum insulin, triglycerides and 2-h 75 g OGTT blood glucose levels. The insulin-resistance markers which have recently been cited as ischemic vascular disease risk factors should be carefully monitored in pill users.

Long-term effects of Depo-Provera on carbohydrate and lipid metabolism

Long-term effects of injection Depo-Provera (depo-medroxyprogesterone acetate) on carbohydrate and lipid metabolism were studied in 157 women who were treated continuously for a mean duration of 43.3 months. The patients were matched with 162 controls for race, age, parity and height. Glucose tolerance was impaired with higher intolerance at longer duration. Glucose areas were significantly higher at 48 and 60 months of injection. Insulin levels were also significantly decreased at 30 minutes and increased at 150 minutes but the area was normal. Triglycerides were initially decreased, being significant at 36 months (p less than 0.001) and returned to normal at 60 months while cholesterols were significantly higher at 24 and 36 months (p less than 0.05) and 60 months (p less than 0.001). In view of these findings, Depo-Provera may have an advantage over oral pills on a short term basis as there are less alterations in carbohydrate and lipid metabolism.

Low dose injectable contraceptive norethisterone enanthate 20mg monthly - II. Metabolic side effects

Metabolic effects of a long-acting low dose injectable contraceptive, norethisterone enanthate 20-mg, monthly injections (Neten-20), was tested in 13 women belonging to the low income groups over a period of 1 year. No change was observed in hemoglobin, hematocrit, glucose tolerance, plasma lipids, iron, calcium, or serum glutamate-oxaloacetate transaminase after treatment. Marginal rise in albumin and fall in some globulin fractions was observed. The slight fall seen in serum alkaline phosphatase could be attributed to a change in lactation status. Vitamin A, pyridoxine and riboflavin status were not altered. A peculiar aberration in the tryptophan-niacin pathway as indicated by rise in kynurenic acid excretion after tryptophan load was observed. This could be corrected by multivitamin therapy. These data suggest that the use of Neten-20 for one year does not lead to adverse metabolic effects analogous to those seen with combination type oral contraceptives.

Clinical perspectives in the care of the pregnant diabetic patient

Despite the considerable improvement in the care of the diabetic mother and the prognosis for her baby, a number of clinical problems remain unresolved. Apart from the increased incidence of major and minor fetal anomalies, morbidity amongst the newborn and the high incidence of diabetes in later life of women who have had relatively minor carbohydrate intolerance during pregnancy are a cause for concern. In this paper the outstanding clinical problems and thier possible solutions are considered. The elucidation of the origin of congenital malformations is discussed. The prevention of congenital anomalies in the diabetic requires a precise knowledge of their aetiology which is currently not available. However, on the hypothesis that diabetes creates an abnormal biochemical environment which may well disturb embryogenesis, it is logical to try and control maternal blood sugar as soon as possible in pregnancy or even before conception. To extend this argument further, it follows naturally that the maintenance of normoglycaemia throughout pregnancy until delivery is also desirable. The practicalities of various methods of screening for diabetes in pregnancy and new approaches in the medical and obstetric problems of the pregnant diabetic are also considered. Finally, the question of contraception and its implication for the woman who is known to have carbohydrate intolerance in pregnancy is discussed.

Comparison of ethinylestradiol and mestranol in sequential-type oral contraceptives in their effects on blood glucose and serum insulin in oral glucose tolerance tests

Forty 3-hour oral glucose tolerance tests (OGTTs) were performed in 10 assumedly healthy female volunteers 19 to 30 years old, each serving four times as her own control. Each subject was taking a sequential type oral contraceptive containing either 50 microgram of ethinylestradiol or 80 microgram of mestranol alternatingly in four consecutive treatment cycles. The OGTTs were performed on the 6th day of each cycle, during pure estrogen medication. Blood glucose and serum insulin values did not differ significantly under either estrogen as tested by the t-test for paired observations. Our results do not support the findings of others that mestranol has a more pronounced or even exclusively adverse effect on glucose tolerance as compared with ethinylestradiol.