Erica B. Monasterio and Mary-Ann Shafer
Close to 800,000 adolescents between 15 and 19 years old in the United States experience a pregnancy each year, with approximately 30% of these pregnancies terminated by therapeutic abortion, 14% resulting in spontaneous abortion, and the balance resulting in a live birth. Although these data reflect a significant issue impacting adolescent health and well-being, trends in pregnancy, abortion, and birth among US adolescents continues on a downward trend over the past 25 years.1 Of those who maintain the pregnancy to term, about 95% of adolescents decide to parent the child, and 79% of teen mothers are unmarried.2 The factors that place young women at risk for an unintended pregnancy and the interactions among these factors are complex. Lack of appropriate knowledge regarding sexual intercourse and contraception plays a role in the perpetuation of myths regarding risk for pregnancy, especially among younger teenagers. Cognitive immaturity results in adolescents’ difficulty in linking the act of sexual intercourse with the possible outcome of pregnancy and therefore assessing their true personal risk for pregnancy as well as difficulty in applying information that they may have to their own decision-making related to sexual behavior and pregnancy prevention. Environmental factors including poverty, community norms, and cultural expectations make teenage parenthood an attractive alternative role for many young women. Also, society’s ambivalence regarding adolescent sexual activity, contraception, pregnancy, and teenage parenthood acts as a barrier to the development and maintenance of effective interventions.
INTRAUTERINE PREGNANCY
During any assessment of a female adolescent, it is advisable to record the date and normality of the last menstrual period. A history of unprotected intercourse since the last menses with or without amenorrhea or unusual vaginal bleeding should alert the physician to the possibility of pregnancy. The absence of historical information does not preclude pregnancy because often the adolescent is unwilling to communicate sexual information to the clinician. In addition to amenorrhea or a “missed period,” the typical symptoms associated with pregnancy (nausea, vomiting, intermenstrual spotting, breast tenderness, unexplained weight gain, urinary frequency, and fatigue, among others) may be present in any combination or may be absent early in pregnancy.
EVALUATION FOR PREGNANCY
A physical assessment, including a pelvic examination, is critical to the evaluation of a possible pregnancy. The pregnancy test confirms the presence of an early pregnancy, using detection of β-human chorionic gonadotropin (β-HCG) in the urine. Within 24 hours of implantation, the placenta initiates production of HCG (≥ 5 mIU/mL), and concentrations double every 48 to 72 hours in a normal pregnancy. By 2 weeks, the level rises to more than 200 mIU/mL in a normal pregnancy, and concentration peaks at approximately 100,000 mIU/mL at 6 to 8 weeks. Thereafter, the level drops to below 10,000 mIU/mL by 14 weeks. Currently, urine testing using monoclonal antibodies to β-HCG provides an accurate, sensitive, easy, and inexpensive screening tool to detect early pregnancy with sensitivities to levels of 5 to 50 mIU/mL. Thus, testing performed as early as 1 week postimplantation will be positive for 98% of women, and for tests with a sensitivity of 25 mIU/mL, testing can be positive as early as 3 to 4 days postimplantation (7–10 days postfertilization).3
COUNSELING AND MANAGEMENT
Once the presence and gestation of an intrauterine pregnancy are established by pelvic examination and pregnancy testing, counseling with the adolescent (and, desired by the adolescent patient, with the parent or parents, other responsible adult, and/or partner) should explore options for pregnancy management. These include continuance of pregnancy, parenting, adoption, and termination of pregnancy. Such counseling should begin in the office setting and can continue at an appropriate referral agency. Confidentiality should be offered to the adolescent and maintained at the request of the adolescent, based on state minor consent laws, as appropriate.
ECTOPIC PREGNANCY
EPIDEMIOLOGY
Ectopic pregnancy is an expanding problem for young, sexually active women, as reflected by a fourfold increase in incidence of the problem between 1970 and 1992, with 20 ectopic pregnancies reported per 1000 pregnancies in 1992. It is the leading cause of maternal death in the first trimester of pregnancy, the second leading cause of overall maternal death, and occurs in 1.5% of all pregnancies.4 Approximately 98% of ectopic pregnancies conceived naturally occur in the fallopian tube itself.
PATHOPHYSIOLOGY
The most common factor that predisposes the young woman to tubal damage and therefore ectopic pregnancy is acute salpingitis, especially chlamydial infection. Other predisposing factors include congenital anomalies, previous pelvic or abdominal surgery, and prior ectopic pregnancy. Recent data on the relationship between intrauterine devices (IUD) use and ectopic pregnancy has shown that the use of IUDs does not increase the risk for ectopic pregnancy.5 Less common factors linked to ectopic pregnancy include ectopic endometrial tissue within the tube (endometriosis), multiple sexual partners, cigarette smoking, vaginal douching, and early sexual debut. Although young women ages 15 to 24 years have the lowest incidence of ectopic pregnancy, they have the highest ectopic pregnancy–related death rate, especially among nonwhite teenagers.
CLINICAL FEATURES AND DIFFERENTIAL DIAGNOSIS
The common clinical presentation of an ectopic pregnancy includes lower abdominal pain (100%), amenorrhea (75%), intermenstrual spotting (75%), abdominal tenderness (90%), adnexal tenderness (85%), adnexal/pelvic mass (50%), and uterine enlargement mimicking early changes of pregnancy (>90%). Women with ectopic pregnancies have normal vital signs unless rupture occurs.
The differential diagnosis of the young woman presenting with abdominal pain, amenorrhea, or spotting includes a normal intrauterine pregnancy (IUP), a failing IUP (spontaneous abortion), and an ectopic pregnancy must rule out pelvic inflammatory disease (see Section 3.6), chronic salpingitis, torsion or ruptured ovarian cyst, appendicitis, rupture of an intrauterine device through the uterine wall, and acute gastroenteritis.
DIAGNOSTIC EVALUATION
The quantitative serum pregnancy test is the most important factor in diagnosing ectopic pregnancy. The quantitative β-human chorionic gonadotropin (β-HCG) determines whether a pregnancy is present and, with serial HCG measurements, whether it is normal and intrauterine. Ectopic pregnancy often produces HCG at a slower rate, although there is considerable overlap of concentrations in normal intrauterine and ectopic pregnancies early in gestation. With current sensitive urine tests for pregnancy, urinary testing is acceptable for screening for pregnancy regardless of implantation site. If ectopic pregnancy is suspected, however, a blood sample should be obtained for quantitative β-HCG and should be repeated at 48 hours.
Four clinical laboratory tests and procedures will differentiate among the possible diagnoses: quantitative human chorionic gonadotropin (HCG), serum progesterone, transvaginal ultrasound, and uterine curettage. A viable intrauterine pregnancy is characterized by doubling of the serum β-HCG every 48 to 72 hours or a β-hCG level greater than 25 IU/L, a progesterone level 22 ng/mL or more, and an ultrasound consistent with an intrauterine gestational sac. A failing intrauterine pregnancy is characterized by an abnormally rising (plateau or decreasing level) β-HCG on serial measures, a progesterone level less than 5 ng/mL, and villi obtained by curettage. In contrast, an ectopic pregnancy is defined by a progesterone less than 5 ng/mL, an abnormally rising β-HCG, no villi on curettage, and a transvaginal ultrasound consistent with an extrauterine pregnancy.6
TREATMENT
Management of ectopic pregnancy frequently requires emergent surgical intervention such as laparotomy and salpingectomy on the affected side because of delayed diagnosis and rupture, with subsequent poor fertility prospects. More recently, ectopic pregnancy is recognized earlier, before rupture. This has led to more conservative management approaches being employed that achieve comparable resolution of the ectopic pregnancy but preserve subsequent fertility. These include salpingostomies by laparoscopy and medical management with methotrexate. Candidates for medical management include hemodynamically stable women who are willing and able to comply with posttreatment monitoring, have a serum β-HCG level less than 5,000 IU/L, and have no evidence of fetal cardiac activity on ultrasound.6 Single-dose or multiple-dose methotrexate is given on alternate days (1 mg/kg intramuscularly on days 1, 3, 5, 7) with leucovorin “rescue” added in some protocols on alternative days (0.1 mg/kg intramuscularly on days 2, 4, 6, 8) until β-HCG decreases by 15% or more in 48 hours or 4 doses of methotrexate are completed. Efficacy is increased from 88% to 93% with multiple-dose regimens; single-dose regimens are less expensive, have a more favorable side-effect profile, do not usually require leucovorin rescue, and require less intensive follow-up while being effective for most women.7 Careful weekly follow-up is essential with β-HCG until the titer is less than 5 mIU/mL.
OUTCOMES
The outcome of an ectopic pregnancy depends on the location of implantation. A spontaneous “tubal abortion” is most likely to occur when the site of implantation is in the ampulla of the tube, whereas the more dangerous tubal rupture is most likely with implantation within the tube’s isthmus. When acute rupture into the peritoneum occurs, it is usually accompanied by acute hemorrhage, hypovolemia, and shock, resulting in a life-threatening situation.
Recent advances in determining early pregnancy coupled with the success of conservative management of early ectopic pregnancies discussed above, have decreased mortality and morbidity while preserving fertility.
In addition to pregnancy, the differential to consider when abdominal pain is coupled with menstrual irregularities includes acute or chronic salpingitis, torsion or ruptured ovarian cyst, appendicitis, intrauterine pregnancy complication, and acute gastroenteritis.