Menstrual cycle pattern and fertility: a prospective follow-up study of pregnancy and early embryonal loss in 295 couples who were planning their first pregnancy

Henrik A. Kolstad; Jens Peter Bonde; Niels H. Hjøllund; Tina K. Jensen; Tine B. Henriksen; Erik Ernst; Aleksander Giwercman; Niels Erik Skakkebaek; Jørn Olsen

doi:10.1016/s0015-0282(98)00474-9

Menstrual Cycle Cycle Disorders

Menstrual cycle pattern and fertility: a prospective follow-up study of pregnancy and early embryonal loss in 295 couples who were planning their first pregnancy

Kolstad HA, Bonde JP, Hjøllund NH, Jensen TK, Henriksen TB, Ernst E, Giwercman A, Skakkebaek NE, Olsen J

Published March 5, 1999 Fertility and Sterility, 71(3), 490-496

DOI 10.1016/s0015-0282(98)00474-9 PMID 10065787

RRM Academy Synopsis

Women whose cycle length varied by 10+ days had lower pregnancy odds

In a Danish study of 295 couples planning a first pregnancy, women whose cycle length varied by about 10 days or more had a quarter of the odds of pregnancy per cycle (odds ratio 0.25). The comparison group was women whose cycle showed no variation. Follow-up lasted up to six cycles.

Nearly 5 in 10 couples reached a recognized pregnancy during cycles 2 to 6 of follow-up. Source: Kolstad HA et al., 1999, PMID 10065787.

Study at a glance, prospective cohort study: Women whose cycle length varied 10 days or more had lower pregnancy odds — Study at a glance, prospective cohort study of 295 couples: Women whose cycle length varied 10 days or more had lower pregnancy odds. Source: Kolstad HA et al., 1999, PMID 10065787.

Key Findings

Overall, 139 of the 295 couples (47.1%) reached a recognized pregnancy during cycles 2 to 6 of follow-up.
Fecundity (pregnancy chance per cycle) with cycle length varying by about 10 days or more was about 25% of that with no variation (odds ratio 0.25, 95% confidence interval 0.09 to 0.68).
Crude fecundity was 0.26 with no variation in cycle length and 0.10 with variation of 10 or more days.
Fecundity was highest with a cycle length of 28 to 31 days and no variation, exceeding the lowest group by a factor of eight.
Of 128 conceptions, 106 were recognized pregnancies and 22 ended before recognition. The numbers were too small to confirm a difference in pregnancy survival by cycle pattern.

Interpretation

This prospective cohort study found an association between cycle pattern and pregnancy chance. Couples were healthy, aged 20 to 35, and had no earlier pregnancy. The likely cause may be a problem with ovulation, conception, implantation, or holding a pregnancy. The authors note that longer cycles made up almost all of the extra variation, so the two were hard to tell apart. The findings support larger studies of cycle length changes as a sign of fertility.

RRM Context

Restorative reproductive medicine relies on cycle charting, and cycle length is a basic part of any chart. This study grouped women by cycle length from a daily bleeding diary. The authors propose that finding the causes of abnormal cycle patterns may point to causes of infertility. They suggest women with variable cycles should be evaluated for infertility earlier. Sperm concentration was part of the adjusted analysis.

Our editorial summary of this paper, not the article's abstract.

Abstract

Objective

To characterize how the menstrual cycle pattern relates to fertility regardless of potential biases caused by inappropriate coital timing during the menstrual cycle or early embryonal loss.

Design

Prospective follow-up study.

Setting

Healthy couples recruited throughout Denmark.

Patients

Two hundred ninety-five couples who were planning their first pregnancy were followed up from the discontinuation of birth control until a pregnancy was recognized within six menstrual cycles. Early embryonal losses were detected by changes in urinary hCG levels.

Interventions

None.

Main Outcome Measures

The probability of pregnancy occurring within one menstrual cycle (fecundity).

Results

In women who had a cycle length that differed by >10 days from the usual cycle length, fecundity was approximately 25% that of women who had no variation (odds ratio 0.25, 95% confidence interval 0.09-0.68). When the combined effect of cycle variation and cycle length was assessed, cycle variation was a persistent strong predictor of fecundity.

Conclusions

The mechanisms of the present findings probably are female functional disturbances in ovulation, conception, implantation, or sustained pregnancy, linked with variable menstrual cycle length. Thus, identification of medical and environmental causes of abnormal menstrual cycle patterns may provide clues to the causes of infertility. Moreover, the menstrual cycle pattern also should be taken into consideration in the clinical decision-making process.

Topics

Menstrual Cycle › Cycle Disorders › Ovulatory Disturbances · Reproductive Endocrinology › Ovulation Physiology › Ovulation Disorder Classification

Henrik A. Kolstad, Jens Peter Bonde, Niels H. Hjøllund, Tina K. Jensen, Tine B. Henriksen, Erik Ernst, Aleksander Giwercman, Niels Erik Skakkebaek, Jørn Olsen

H Kolstad, J Bonde, N Hjøllund, T Jensen, T Henriksen, E Ernst, A Giwercman, N Skakkebaek, J Olsen

PMID 10065787 10065787 DOI 10.1016/s0015-0282(98)00474-9 10.1016/s0015-0282(98)00474-9 Kolstad et al. 1999, Kolstad 1999

Keywords

Abortion, Spontaneous/urine, Adult, Chorionic Gonadotropin/urine, Female, Fertility, Follow-Up Studies, Humans, Menstrual Cycle, Pregnancy, Pregnancy Rate, Probability, Prospective Studies, Chorionic Gonadotropin

Menstrual cycle pattern and fertility: a prospective follow-up study of pregnancy and early embryonal loss in 295 couples who were planning their first pregnancy

Women whose cycle length varied by 10+ days had lower pregnancy odds

Key Findings

Interpretation

RRM Context

Abstract

Topics

By this author

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Keywords