Pregnancy loss before the completion of 20 weeks of gestation is defined as miscarriage. The terms miscarriage, spontaneous abortion, and early pregnancy loss are interchangeably used during the first trimester. Pregnancy failure after 20 weeks is labeled as stillbirth or fetal death in utero (FDIU). According to the American College of Obstetricians and Gynecologists (ACOG), 10% of all clinically proven pregnancies end in early pregnancy loss. Additionally, 80% of all losses occur in the first trimester.
What are the types of miscarriages?
Several types have been listed in the literature. The most commonly used classification is:
- Early miscarriage: pregnancy loss in the first 12 weeks of gestation. A chemical pregnancy is an early miscarriage that occurs before five weeks.
- Late miscarriage: pregnancy loss between 12-24 weeks of gestation.
- Threatened miscarriage: vaginal bleeding, but pelvic exam reveals a closed cervical os, and ultrasound demonstrates a viable pregnancy.
- Inevitable miscarriage: vaginal bleeding with pelvic exam findings of open cervical os and anticipated passage of products of conception. Ultrasound can reveal a viable or non-viable fetus.
- Incomplete miscarriage: vaginal bleeding with or without the passage of clots. Ultrasound shows remaining pregnancy tissue within the uterine cavity.
- Complete miscarriage: vaginal bleeding followed by the passage of clots. Ultrasound reveals an empty uterus with no retained products of conception (RPOC).
- Missed miscarriage: Ultrasound findings of non-viable pregnancy in the absence of miscarriage symptoms.
- Recurrent/habitual miscarriage: three or more spontaneous miscarriages.
What are the risk factors and etiology involved?
Several risk factors are associated with miscarriage; advanced maternal age and prior miscarriage are commonly seen. The risk of pregnancy in 20-30 years old women is 9-17%. This increases to 20% at 35 years, 40% at 40 years, and 80% at 45 years.
Certain medications which cross the placenta increase the risk of miscarriage. These include certain antibiotics (macrolides, tetracyclines, sulfonamides, quinolones, and metronidazole), antifungals (oral fluconazole), retinoids, non-steroidal anti-inflammatory drugs (NSAIDs), antipsychotic drugs, methotrexate, and misoprostol.
Maternal comorbidities like diabetes, hypertension, antiphospholipid syndrome, blood dyscrasias (factor V Leiden, thrombophilia, etc.), anatomic abnormalities (septate/bicornuate uterus, submucosal fibroids, cervical incompetence, polyps, etc.) are noted to increase miscarriage risk.
Other risk factors include infections (STDs, German measles, toxoplasmosis, etc.), advanced paternal age, excessive caffeine consumption, cigarette smoking, alcohol intake, use of illicit drugs, food poisoning, exposure to pesticides/heavy metals, extremes of weight, stress, and trauma.
Additionally, a chemical pregnancy is the earliest cause of first-trimester miscarriage and occurs due to implantation failure. A positive pregnancy test (blood or urine hCG) is the only evidence of pregnancy. However, the most typical cause is fetal chromosomal (DNA) abnormalities, which account for roughly 50% of all cases of early pregnancy loss. Moreover, placental abnormalities also lead to miscarriages as the placenta is vital for nutrient and gas exchange between the mother and fetus.
Symptoms, signs & evaluation
Common symptoms include loss of pregnancy symptoms, vaginal bleeding/spotting, lower back/ abdominal cramping, and passage of clots. However, some women may be asymptomatic. The presentation is variable and overlaps with other conditions (normal pregnancy, ectopic pregnancy, molar pregnancy); thus, a thorough evaluation must confirm the diagnosis.
Ultrasound is the modality of choice in determining gestational viability. Quantitative hCG levels aid in determining fetal/embryonic development. Therefore, the American College of Obstetricians and Gynecologists (ACOG) advocates serial hCG levels and serial ultrasounds to determine gestational viability. Transvaginal ultrasound findings of the crown-rump length of 7mm with the absence of fetal cardiac activity or empty gestational sac of 16-24 mm diameter with a decline in serial hCG levels suggest early pregnancy loss.
Management
Bed rest and hormone injections have not proven to be very fruitful in preventing miscarriages but are still suggested by many physicians. The beneficial role of aspirin and anticoagulants has been noted in women with antiphospholipid syndrome.
Treatment options include expectant management, medication, and surgical management. Expectant management observes natural miscarriage at home, and little evidence exists to support this option’s safety, so it is not very frequently recommended. The medical treatment uses a prostaglandin analog, misoprostol, which can induce the passage of products of conception with complete expulsion within three days in most cases. However, no contraindication should be present before drug use. Surgical intervention (uterine curettage) is the preferred management mode in emergency cases (profuse hemorrhage) and in those with signs of infection, comorbidities, or contraindications to medical treatment.
Since pregnancy loss takes a toll on the emotional and mental well-being of the patient and their family, psychological consultation should always be considered.
An insight from mamahood
Pregnancy loss at any gestational age can be devastating, and many women resort to self-blame. The grieving mother needs to express her emotions and rely on friends, family, and healthcare providers in order to heal. Regular follow-ups with your physician and psychologist are necessary to address any concerns about emotional/mental health and future pregnancy plans.
