Sarah Lewit

Evaluation of Intrauterine Devices: Ninth Progress Report of the Cooperative Statistical Program

This report, by Christopher Tietze, MD, Associate Director of The Population Council’s Bio-Medical Division, and Sarah Lewit, Research Associate in the Bio-Medical Division, is perhaps best introduced by quoting from Louis M. Hellman, MD, Professor and Chairman of the Department of Obstetrics and Gynecology, State University of New York, College of Medicine:

Recommended Procedures for the Statistical Evaluation of Intrauterine Contraception

The article was prepared for clinical research workers. It lists and describes statistical procedures for evaluating IUDs if less than 10% of the group is lost to follow up giving definitions of terms type of information to include how to calculate net and gross cumulative termination rates using a life table approach and an easy method for estimating 95% confidence limits.

Joint Program for the Study of Abortion (JPSA): Early Medical Complications of Legal Abortion

In the United States, as in many other countries, the appropriate public policy to be taken with regard to induced abortion has become a matter of growing concern in recent years. The philosophic and ethical issues have been analyzed and reanalyzed, argued and reargued, but no resolution is in hand or in prospect. Perhaps for this reason, more attention has recently been given to the social, demographic, and medical aspects of the matter. This publication is a pioneering study to that end.

Men with vasectomies: a study of medical, sexual, and psychosocial changes.

&NA; Responses to questionnaire interviews of 73 men who had undergone vasectomies are discussed, and summary tables presented. The questions cover personal characteristics, the operation itself, motivational factors, and outcome of the operation. Analysis of the outcome includes pre‐ and postoperative physical health; sexual behavior; psychosocial adjustment factors‐‐including marital, job, and community relationships and concern over children; satisfaction with the operation; and social behavior with regard to the operation. On most of these questions the respondent was also asked to evaluate his wifes condition, behavior, or attitude. Medical aspects of the vasectomy and postoperative sperm tests are also discussed.

Statistical evaluation of contraceptive methods: Use-effectiveness and extended use-effectiveness

The recent advent of national family planning programs and the expansion of local programs have created an acute need for accurate statistical evaluation of contraceptive methods. Effectiveness in terms of pregnancy rates and continuation or discontinuation of use of the contraceptive method or methods under study have emerged as the major criteria in such evaluations.

STATISTICAL EVALUATION OF CONTRACEPTIVE METHODS

A methodology for the statistical evaluation of the effectiveness and acceptability of 2 groups of contraceptive methods utilizing life-table procedures adapted for this purpose is described. 2 sets of illustrative tables one for clinical data on IUDs and the other for clinical data on oral medication which is also applicable to other methods of contraception that can be discontinued by the user at any time are presented. The procedures for the statistical analysis of use-effectiveness of which the 2 most important components are the antifertility effect expressed as the rate of accidental pregnancy and acceptability as reflected in the rate of continued use are described. To measure use-effectiveness by life-table procedures certain infomrati on is required: 1) the period covered by the study; 2) the number of women who accept the method (for IUDs the number of first insertions) by date of acceptance; and 3) for each termination the date of acceptance and the reason for discontinuing the contraceptive method by duration of use (ordinal months of use). Numerous self-checking features are included in the analysis.

Use-Effectiveness of Oral and Intrauterine Contraception

The use-effectiveness of oral contraception and intrauterine contraception was studied in 3 family planning centers in the United States: Grady Memorial Hospital in Atlanta, Georgia; State University of New York, Downstate Medical Center, in Brooklyn; and the Planned Parenthood Center in Buffalo, New York. In each locality 1000 women were selected for the study. 2900 women accepted intrauterine devices (IUDs) or oral contraceptives (OCs) as their first method of contraception. In Brooklyn 3 out of 4 women chose OCs; in Atlanta and Buffalo roughly equal numbers selected each method. The mean age of admission was 25.7 years in Buffalo, 24 years in Brooklyn, and 23.8 years in Atlanta. IUD acceptors were older than those choosing OCs. The difference was greatest in Buffalo (3.3 years) and smallest in Atlanta (.8 years). A special one-page, self-coding questionnaire was designed to collect the information required. In all 3 clinics contraceptive termination rates were markedly lower for the IUDs than for OCs. At 1 year of use for the first method only about one-fourth the women who chose the IUD had discontinued its use. Women on OCs terminated at rates from 10-20% higher. Termination rates for all contraception, both first-method and substitution, were lower than for first-method alone and lower for IUDs than for OCs. The highest continuation rate for all contraception was 92.5% for IUD users in Brooklyn while OC users in Atlanta were at the lowest level at 60.5%. Pregnancy rate studies demonstrated higher failure rates with OCs than with IUDs in all 3 clinics. Statistics by age showed that termination rates for both IUD and OC users declined with age. Women who selected IUDs as their method of contraception were more persistent users of contraception. Even after discontinuing IUD use, they were more likely to adopt another contraceptive method.

Outcome of pregnancy with intrauterine devices

Abstract Cumulative rates of abortion, computed by life table methods, among 722 women in the Cooperative Statistical Program for the Evaluation of Intrauterine Devices, who became accidently pregnant and whose pregnancies were undisturbed prior to the diagnosis, were 53.9 per 100 women with a tailed IUD in situ, 42.6 per 100 women with a tailless device in situ, and 32.6 per 100 women with the position of the IUD undetermined at the time of conception. Excluding periods of gestation following manipulation, i.e., removal of the IUD and/or probing of the uterus after the pregnancy had been diagnosed, increases the cumulative abortion rate for women with tailed devices in situ, lowers the rate for women with tailless IUDs in situ, and leaves the rate unchanged for women with the position of the IUD undetermined. For tailed IUDs in situ, the cumulative abortion rate was lowest based on periods following manipulation. For tailless devices in situ, the rate was twice as high after manipulation. The data suggest that (a) the IUD sometimes interferes with the course of the pregnancy, (b) removal of the tailed IUD improves the chances of a live birth, and (c) manipulation in pregnancies with a tailless IUD in situ increases the chances of abortion.

Comparison of the Copper-T and Loop D: a research report.

A research report on the comparison of the Copper-T (TCu) and Lippes loop size D IUDs is presented. The results are from 1-years experience in the double-blind study conducted under the cooperative Statistical Program of the Population Council. 945 TCus and 750 loop Ds were inserted. Rates of expulsion were considerally lower for the TCu than for the loop D. The termination rate for 1 year of use was 23.5/100 1st insertions for the TCu and 29.8/100 for loop D. Excluding Clinic A which accounted for 11 pregnancies with use of TCu or about 2/3 of the pregnancies during the 1st year the pregnancy rate was less than 1/100. Expulsion and removal rates for bleeding and/or pain for the TCu were about 1/2 the comparable rates of loop D. Total event rates were 21 for the TCu and 28.6 for loop D (p less than .02 for pregnancies and p less than .01 for expulsion removals for bleeding and/or pain and total event rates).

Mortality and Fertility Control

The authors present a continuation of the thesis suggesting that the most rational procedure for regulating fertility is a perfectly safe, even though not completely effective, contraceptive method combined with safe methods for terminating pregnancy when the contraceptive fails. This analysis demonstrates that, compared with the risk of death from pregnancy and childbirth, major reversible methods of fertility control—the pill, IUDs, condoms, and diaphragms—and abortion are associated with very low levels of mortality. The exception to this statement is pill use after age 40 by women who smoke. This analysis also confirms the very low mortality associated with using the condom and diaphragm with early induced abortion as a backup to terminate pregnancies resulting from contraceptive failures.