Abortion
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Here is a general overview of abortion, drawing from medical textbooks and clinical sources.
Abortion: General Overview
Definition
Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus before it is viable (capable of surviving outside the uterus - generally before 20 weeks of gestation). The term comes from the Latin aboriri, meaning "to miscarry."
Types of Abortion
By Cause
| Type | Description |
|---|---|
| Spontaneous abortion (miscarriage) | Natural pregnancy loss before 20 weeks, most often in the first 12 weeks. Occurs in ~25-30% of recognized pregnancies. |
| Induced abortion | Medically or surgically initiated termination before viability (before ~20 weeks). |
| Threatened abortion | Bleeding during early pregnancy with the possibility of loss; occurs in ~25% of clinical pregnancies. About half of these ultimately abort. |
| Habitual (recurrent) abortion | Spontaneous loss in three or more consecutive pregnancies. |
| Complete abortion | All products of conception are expelled from the uterus. |
| Incomplete abortion | Some products of conception are retained. |
| Missed abortion | The embryo or fetus has died but is retained in the uterus. |
(The Developing Human: Clinically Oriented Embryology)
Methods of Induced Abortion
There are two main approaches:
1. Medication Abortion ("the abortion pill")
- Uses mifepristone (blocks progesterone) followed by misoprostol (causes uterine contractions).
- Suitable for early pregnancy (generally up to 10-12 weeks, varies by protocol).
- Success rate: >96%.
- Can take place at home or in a clinic.
- Resembles a miscarriage in process.
- Requires follow-up to confirm complete expulsion.
- Does not treat ectopic pregnancy.
2. Surgical Abortion
- Aspiration / vacuum aspiration (D&C): Used up to ~13 weeks. A quick in-office or clinic procedure. Success rate >98%.
- Dilation and Evacuation (D&E): Used in the second trimester (14-24 weeks). Requires cervical preparation.
- Induction abortion: Used late in pregnancy; labor is induced with medications.
(Pfenninger and Fowler's Procedures for Primary Care; Berek & Novak's Gynecology)
Safety
- When performed legally and using WHO-recommended methods, abortion is one of the safest medical procedures.
- The WHO classifies comprehensive abortion care as an essential health service.
- Unsafe abortions (performed outside medical standards or where restricted/illegal) cause approximately 47,000 deaths per year globally.
- In countries with legal access, unsafe abortions are rare; in countries where it is restricted or illegal, complications are very common.
Epidemiology
- Globally, ~3 out of 10 pregnancies end in induced abortion.
- About 56 million induced abortions occur per year worldwide.
- Roughly half (25 million) are classified as "unsafe."
- Abortion rates are highest in areas where access to contraception is limited.
(Berek & Novak's Gynecology)
Causes of Spontaneous Abortion
- Chromosomal abnormalities (most common cause - ~50-60% of first-trimester losses)
- Uterine structural problems
- Hormonal factors
- Infections
- Maternal systemic illness
- Advanced maternal age
Legal and Ethical Context
Abortion law varies widely by country. In some nations, it is broadly legal; in others, it is restricted to specific circumstances (rape, fetal anomaly, maternal health risk) or banned outright. The WHO states that restricting legal access does not reduce the number of abortions, but does significantly increase the proportion that are unsafe. Ethical and religious perspectives on abortion vary greatly and remain subjects of ongoing societal debate.
If you want to go deeper into any specific aspect - the clinical procedure details, causes of miscarriage, global policy, or the pharmacology of mifepristone/misoprostol - just ask.
Recurrent pregnancy loss
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Here is a thorough overview of recurrent pregnancy loss (RPL) based on current medical textbooks.
Recurrent Pregnancy Loss (RPL)
Definition
RPL is traditionally defined as 3 or more consecutive spontaneous pregnancy losses before 20 weeks of gestation. However, current guidelines (ASRM) support beginning clinical evaluation after 2 consecutive losses, as the prevalence of abnormal workup findings is similar between women with 2 vs. 3 or more losses. RPL affects approximately 1% of women trying to conceive.
- Berek & Novak's Gynecology, p. 1791
Epidemiology and Prognosis
Despite the distressing history, most women with RPL will still achieve a successful pregnancy:
| Prior Losses | Risk of next loss |
|---|---|
| 2 | ~24% |
| 3 | ~30% |
| 4 | ~40-50% |
Predicted live birth success based on age and loss history (Creasy & Resnik):
| Age | 2 losses | 3 losses | 4 losses | 5 losses |
|---|---|---|---|---|
| 25 | 89% | 86% | 82% | 79% |
| 30 | 84% | 80% | 76% | 71% |
| 35 | 77% | 73% | 68% | 62% |
| 40 | 69% | 64% | 58% | 52% |
Even women aged 40+ with 6 or more prior losses have a >45% chance of live birth without any specific intervention.
Etiology
About 50% of RPL cases have no identifiable cause ("unexplained RPL"). When a cause is found, the breakdown is:
| Cause | Frequency |
|---|---|
| Fetal aneuploidy (de novo) | ~60% of first-trimester losses overall |
| Parental chromosomal abnormality | 2-5% |
| Antiphospholipid syndrome (APS) | ~15% |
| Anatomic uterine anomalies | 10-12% |
| Endocrine disorders | ~10% |
| Other/unexplained | ~50% |
(Berek & Novak's Gynecology, p. 1792)
1. Genetic Factors
- Fetal aneuploidy is the most common cause of first-trimester loss. Importantly, as the number of prior losses increases, the proportion of losses caused by fetal aneuploidy decreases, and euploid losses become more common - suggesting non-chromosomal mechanisms dominate in true RPL.
- Parental balanced translocations (reciprocal or Robertsonian) are found in 3-5% of RPL couples vs. 0.2-0.7% in the general population. Balanced translocations produce unbalanced gametes that result in non-viable embryos.
- Diagnosis: G-band metaphase karyotype for both partners.
2. Antiphospholipid Syndrome (APS)
APS is the only treatable immunologic cause with strong evidence. Diagnosis requires:
- Clinical criteria: 3+ consecutive losses <10 weeks, OR 1+ fetal death ≥10 weeks with normal morphology, OR 1+ premature birth ≤34 weeks from preeclampsia/placental insufficiency.
- Lab criteria (positive on 2 occasions, ≥12 weeks apart):
- Lupus anticoagulant
- Anticardiolipin antibodies (IgG or IgM), medium-to-high titer
- Anti-β2-glycoprotein-1 antibodies (IgG or IgM) >99th percentile
Mechanism: antiphospholipid antibodies promote a prothrombotic placental environment and may inhibit syncytiotrophoblast formation.
Treatment: low-dose aspirin + low molecular weight heparin (LMWH) during pregnancy.
3. Uterine Anatomic Factors
- Congenital Mullerian anomalies (septate, bicornuate, unicornuate uterus) are found at higher rates in RPL patients.
- Uterine septum is the most clinically significant - resection by hysteroscopy can improve outcomes.
- Acquired defects: fibroids (particularly submucosal), intrauterine adhesions (Asherman syndrome), polyps.
- Evaluation: 3D transvaginal ultrasound (preferred), sonohysterography, hysterosalpingography (HSG), or MRI.
4. Endocrine Factors
- Hypothyroidism / antithyroid antibodies: TSH cutoffs during pregnancy are debated (many recommend <2.5 mIU/mL). Positive anti-TPO antibodies are associated with higher miscarriage rates, even with a normal TSH.
- Hyperprolactinemia: causes ovulatory dysfunction and luteal phase defects; normalization with dopamine agonists may improve outcomes.
- Poorly controlled diabetes: HbA1c elevation is associated with RPL.
- Diminished ovarian reserve (DOR): associated with higher aneuploidy rates, explaining RPL through a chromosomal mechanism.
5. Thrombophilias
- Inherited thrombophilias (Factor V Leiden, prothrombin gene mutation, protein C/S deficiency, antithrombin III deficiency) have been proposed as causes.
- However, current ASRM and ESHRE guidelines do not recommend routine thrombophilia screening for RPL - evidence supporting anticoagulation for inherited thrombophilias (outside APS) is insufficient.
6. Infectious Causes
- Mycoplasma, Ureaplasma, Chlamydia, bacterial vaginosis, and viral agents (HSV, CMV) have been studied.
- Evidence for a direct causal role in RPL remains weak and inconsistent. Routine infectious screening is not recommended.
7. Male Factors
- Seminal oxidative stress has been associated with RPL in recent systematic review evidence (PMID: 40494067), though this remains an emerging area.
Workup / Evaluation
Recommended testing (ASRM/ESHRE):
| Domain | Tests |
|---|---|
| Genetic | Parental peripheral blood karyotype (both partners); chromosomal microarray on products of conception |
| Uterine anatomy | 3D transvaginal ultrasound, sonohysterography, or HSG; hysteroscopy if indicated |
| Antiphospholipid | Lupus anticoagulant; anticardiolipin IgG/IgM; anti-β2-glycoprotein-1 IgG/IgM |
| Endocrine | TSH, anti-TPO antibodies; prolactin; HbA1c |
Not routinely recommended:
- Inherited thrombophilia panel (outside research setting)
- ANA and other autoantibodies
- Infectious screening
- Ovarian reserve testing (FSH, AMH) as a standard workup item
(Creasy & Resnik's Maternal-Fetal Medicine, p. 979)
Management / Treatment
Specific treatments (evidence-based):
| Cause | Treatment |
|---|---|
| APS | Low-dose aspirin + LMWH through pregnancy |
| Uterine septum | Hysteroscopic resection |
| Hypothyroidism | Levothyroxine (target TSH <2.5 mIU/mL in pregnancy) |
| Hyperprolactinemia | Dopamine agonist (bromocriptine/cabergoline) |
| Poorly controlled diabetes | Glycemic optimization (HbA1c target <6.5%) |
| Parental translocation | IVF with preimplantation genetic testing (PGT-A) - see below |
Controversial / investigational:
- IVF + Preimplantation Genetic Testing for Aneuploidy (PGT-A): A 2025 meta-analysis (PMID: 39151684) analyzed PGT-A for unexplained RPL - evidence remains mixed.
- Progesterone supplementation: Used widely in clinical practice for threatened/early RPL; evidence in unexplained RPL is debated.
- Immunosuppressive therapy (e.g., corticosteroids, IVIg): Not recommended outside clinical trials.
- Leukocyte immunization therapy: No proven benefit; not recommended.
- Low molecular weight heparin for non-APS thrombophilia: Not supported by current evidence.
Universal supportive care:
- Serial serum beta-hCG monitoring from missed period until ultrasound viability confirmed (~1,200-1,500 mIU/mL)
- Early first trimester ultrasound surveillance
- Psychological support - shown to improve outcomes even in unexplained RPL
- Karyotypic analysis of all future miscarriage tissue (by comparative genomic hybridization/CMA preferred; >90% success rate vs. ~60-80% for traditional karyotype)
Key Clinical Pearls
- The most common single chromosomal cause in early losses is trisomy (especially trisomy 16) and monosomy X (most common in anembryonic pregnancies).
- Pregnancy losses after 10 weeks are less likely to be aneuploid - other causes (APS, uterine) should be more strongly suspected.
- Documenting aneuploidy in a loss specimen has prognostic and emotional value - it may indicate a "random" event rather than a recurring pathology.
- The prognosis after RPL remains generally optimistic with proper management and surveillance.
(Sources: Berek & Novak's Gynecology; Creasy & Resnik's Maternal-Fetal Medicine)
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