The Postpartmn Papanicolaou SlDear

This study was performed to evaluate the importance of obtaining postpartum Papanicolaou (Pap) smears routinely. Four hundred eighty-nine patients receiving pregnancy care had a normal prenatal Pap smear and a repeat Pap smear at their postpartum visit. Twenty-four (4.9 percent) had an abnormal postpartum Pap smear (95 percent confidence interval: 3.1-6.9 percent). Twenty-one (87.5 percent) of the abnormal smears showed squamous dysplasia; three (12.5 percent) showed squaCervical cytology. screening with Papanicolaou (Pap) smears has become a standard part of preventive medical care. l The procedure is considered by many to have been an important factor in decreasing mortality from cervical cancer over the past several decades.2 Traditionally, Pap smears have been recommended annually. In the early 1970s, however, epidemiologic evidence indicated that serious cytologic abnormalities on cervical Pap smears developed slowly. The average length of time between first development of mild dysplastic changes and subsequent development of cervical carcinoma was estimated to be as long as 7 to 10 years. 3 This knowledge led the American Cancer Society (ACS) to recommend, in 1980, that all women (except those at high risk for cervical cancer) should have a cervical Pap smear every 3 years (rather than annually) after initially having normal smears for 2 years.4 More recent evidence, however, has indicted that the time period between initial development of mild cytologic abnormalities and subsequent progression to carcinoma may be shorter than when the American Cancer SOciety4 made its 1980 recommendations. Genital infections with human papilloma virus (HPV), the probable etiologic agent of cervical cancer, are increasing in frequency,5 and certain strains of HPV appear to be accelerating the rate at which cervical neoplaFrom the Section of Family Medicine, Department of Family and Community Medicine, University of Arizona College of Medicine, Tucson, AZ 85719. Supported, in part, by a research grant from the Family Health Foundation of America. mous atypia. No specific risk factors were identified that predicted the occurrence of an abnormal postpartum Pap following a normal prenatal Pap except for age. Women more than 30 years of age were less likely to have an abnormal postpartum Pap smear (P = 0.008). The results of this study support the practice of performing Pap smears during prenatal care and again at postpartum examination, even when the prenatal Pap smear is normal. (J Am Bd Fam Pract 1989; 2:4-9.) sia develops; in some cases, the interval can be as short as 1 year. 6 In recognition of this apparent change in the epidemiology of cervical neoplasia, the American Cancer Society and six other health professional organizations* recently revised their recommendations about Pap smear screening.' The new ACS guidelines state that all women who are, or who have been, sexually active, or have reached 18 years, should have an annual Pap test and pelvic examination. After a woman has had three or more consecutive normal annual examinations, the Pap test may be performed less frequently at the discretion of her physician. ' Despite widespread dissemination and general acceptance of these ACS guidelines, it is not clear how physicians apply the guidelines to pregnant women. Many physicians perform two Pap smears during the course of routine pregnancy care. One Pap smear is performed at the beginning of prenatal care and another at the postpartum visit, even though the postpartum visit occurs less than i year later. Postpartum Pap screening commonly occurs even when the prenatal Pap smear is normal and even when the woman is not at increased risk for cervical cancer. This practice is supported by the only standard textbook that specifically discusses details of the postpartum examination. *The other organizations included the National Cancer Institute, the American Academy of Family Physicians, the American College of Obstetricians and Gynecologists, the American Medical Association, the American Nurses Association, and the American Medical Women's Association. 4 The Journal of the American Board of Family Practice-Vol. 2 No. 1 / January March 1989 Abnormal Pap smears are infrequent during pregnancy. Research published in the 1970s, before the recent increase in HPV infections, suggested that the frequency of a cytologic abnormality on prenatal Pap smears was low (1-2 percent) and that the frequency of carcinoma was very small (0.19-0.5 3 percent).9-11 In addition, although the issue has not been studied since 1981, among women with abnormal prenatal Pap smears, pregnancy has not been thought to accelerate or worsen dysplastic and malignant cytologic changesY-14 It is not clear, therefore, whether pregnant women who have normal prenatal Pap smears require routine postpartum Pap smear testing to detect whether cervical neoplasia developed during the course of pregnancy. The risk from not doing postpartum Pap smears would seem to be quite low, and the cost savings could be about $55,500,000 (3,700,000 births annually I 5 multiplied by $15 per Pap smear). This study, therefore, was designed to evaluate the necessity and usefulness of performing routinely a postpartum Pap smear on women whose prenatal Pap smear was normal. The hypothesis was that no woman with a normal Pap smear during prenatal care would be found to have an abnormal Pap smear at postpartum examination. Methods The Study Population The potential sample included 909 women who presented for prenatal care at the Family Practice Clinic (FPC), University of Arizona College of Medicine, between 1979 and 1987. The FPC is a large ambulatory health facility with approximately 22,000 patients per year. Prenatal care and delivery are provided by family practice residents and faculty physicians. Patients were included in this study if they met the following criteria: received initial prenatal care at the FPC; had a Pap smear obtained during prenatal care, and the results were available; had a Pap smear at the postpartum examination, and the results were available. We included patients who might have been referred to the University's high-risk obstetrical clinic and whose postpartum Pap smears were obtained there. Data Collection A research assistant reviewed the 909 medical records. In addition to identifying eligible patients, the following additional information was used: (1) results of prenatal Pap smear; (2) results of postpartum Pap smear; (3) demographic data, including age, race, marital status, education level, and type of payment; and (4) medical information, including gravidity, parity, and history of various sexually transmitted diseases (genital herpes simplex infections, syphilis, and gonorrhea). Information about infection with human papillomavirus was not routinely obtained because its relation to cervical cancer was not widely known during the early years of data collection. Definition of Normal and Abnormal Pap Smears All Pap smears were obtained, using standard techniques, by faculty physicians or by residents and medical students under their supervision. An endocervical specimen was obtained by inserting a cotton-tipped applicator into the endocervical canaL rotating the applicator, and then transferring the specimen to a glass microscope slide. An exocervical specimen was obtained by scraping the exocervix with a standard Pap smear scraper and transferring the specimen to a separate microscope slide. Specimens were fixed immediately using standard commercial fixatives (containing 2-propanol, 2-propanone, and polyethylene glycol) and sent to the University of Arizona Medical Center clinical laboratory for interpretation by a trained cytotechnician. All specimens interpreted as abnormal by a cytotechnician were reviewed by a cytopathologist. The following cytologic interpretations were considered normal: "normal," "squamous metaplasia," "inflammatory atypia," and "inflammation" (if no squamous atypia or dysplasia were noted). Interpretations were considered abnormal if any of the following degrees of cervical intraepithelial neoplasia (CIN) were reported: "squamous atypia," "squamous dysplasia" (either mild, moderate, or severe), or "carcinoma." Statistical Analysis The chi-square statistic and analysis of variance were used to evaluate data for significant differ~ ences between patients with normal versus abnor~ mal postpartum Pap smears for the various demographic and medical variables listed previously. Significance was defined as a P value of less than 0.05. Postpartum Pap Smear ,