What are the evaluation recommendations for a late menstrual period (late period)?

From the Guidelines

For a late menstrual period, I strongly recommend first taking a home pregnancy test, as pregnancy is a common cause of missed periods, and if negative, consider scheduling an appointment with your healthcare provider for evaluation, especially if your period is more than one week late or if you have concerning symptoms like severe pain or abnormal bleeding. According to the U.S. Selected Practice Recommendations for Contraceptive Use, 2013 1, a healthcare provider can be reasonably certain that a woman is not pregnant if she has no symptoms or signs of pregnancy and meets any one of the following criteria: is ≤7 days after the start of normal menses, has not had sexual intercourse since the start of last normal menses, has been correctly and consistently using a reliable method of contraception, is ≤7 days after spontaneous or induced abortion, is within 4 weeks postpartum, or is fully or nearly fully breastfeeding, amenorrheic, and <6 months postpartum.

Some key points to consider when evaluating a late menstrual period include:

• The likelihood of ovulation is low from days 1–7 of the menstrual cycle 1
• Pregnancy tests often are performed before initiating contraception, but the accuracy of qualitative urine pregnancy tests varies depending on the timing of the test relative to missed menses, recent sexual intercourse, or recent pregnancy 1
• For contraceptive methods other than IUDs, the benefits of starting to use a contraceptive method likely exceed any risk, even in situations in which the healthcare provider is uncertain whether the woman is pregnant 1
• Medical evaluation may include a physical exam, blood tests to check hormone levels (including hCH, TSH, prolactin, and FSH), and possibly a pelvic ultrasound, as recommended by the American College of Obstetricians and Gynecologists (ACOG) 1

While waiting for your appointment, it is essential to track any symptoms you experience and note recent lifestyle changes, stress levels, weight fluctuations, or new medications, as many factors can cause menstrual irregularities, including stress, significant weight changes, excessive exercise, hormonal imbalances, polycystic ovary syndrome, thyroid disorders, and perimenopause 1. Most causes are not serious and can be addressed with lifestyle modifications or medication, but proper evaluation is crucial to rule out more serious conditions and develop an appropriate treatment plan.

From the Research

Evaluation Recommendations for Late Menstrual Period

• Pregnancy should be ruled out before proceeding with diagnostic evaluation, as it is the most common cause of amenorrhea 2, 3
• A careful history and physical examination may reveal evidence of androgen excess, estrogen deficiency, or other endocrinopathies 2
• Serum prolactin and thyroid-stimulating hormone (TSH) levels should be checked in all women who are not pregnant 2
• If serum prolactin and TSH levels are normal, a progesterone challenge test should be performed to determine outflow tract patency and estrogen status 2
• In women with hypoestrogenic amenorrhea, serum gonadotropin, follicle-stimulating hormone, and luteinizing hormone levels may be measured to determine whether amenorrhea represents ovarian failure or pituitary or hypothalamic dysfunction 2

Laboratory Assessment

• Initial workup of primary and secondary amenorrhea includes a pregnancy test and serum levels of luteinizing hormone, follicle-stimulating hormone, prolactin, and thyroid-stimulating hormone 3
• Patients with primary ovarian insufficiency can maintain unpredictable ovarian function and should not be presumed infertile 3
• Patients with hypothalamic amenorrhea should be evaluated for eating disorders and are at risk for decreased bone density 3

Special Considerations

• In cases of suspected pregnancy, a definitive pregnancy test or ultrasound scan should be performed to confirm or rule out pregnancy 4
• For pregnant women with a viable fetus (≥ 23 weeks), fetal heart rate auscultation and fetal monitoring can be initiated, and an obstetrical consultation should be obtained as soon as feasible 4