SPONTANEOUS ABORTION

ASSOCIATE PROFESSOR IOLANDA BLIDARU

MD, PhD

DefinitionsThe termination of pregnancy by any means

before the fetus is sufficiently developed to survive.

USA and western European cuntries → the termination of pregnancy before 20 weeks gestation based upon the date of the first day of the LMP.

Another commonly used definition: delivery of product of conception that weighs less than 500g.

In some European countries, including Romania, this definition is confined to the interruption of pregnancy before 24 weeks of gestation, less than l000g (dead) or less than 500g (alive).

Frequency

Approximately 15% to 20% of clinically

recognized pregnancies are aborted

spontaneously.

Abortions

45% in the weeks 5 to 9

35% in the weeks 10 to 14

15% in the weeks 15 to 18

Classification

unique (isolated) or recurrent (3 or more consecutive spontaneous abortions)

early abortions (before 12 weeks) or late abortions (in the 2nd trimester)

threatened, inevitable (or in evolution), incomplete, missed and complete abortion

Etiology

Mechanisms responsible for abortion

I.- mechanical causesII.- infectionsIII.- genetic causesIV.- endocrine causesV.- immunological causesVI.- maternal systemic conditions

I. Mechanical causes

ovular (multiple pregnancy, hydramnios)

uterine defects:

1. - congenital anomalies

2. - uterine malposition (retroversion)

3. - uterine tumors (myomas)

4. - intrauterine adhesions synechiae (Asherman syndrome)

5. - incompetent cervix

II. Infections

Microorganisms associate with spontaneous abortion: - variola - malaria - CMV - Toxoplasma - Mycoplasma hominis - Chlamydia trachomatis - Salmonella typhi - Ureaplasma urealyticum

III. Genetic causes

abnormality of development of the zygote, embryo, fetus and/or the placenta

aneuploidy (abnormal no. of chromosomes )

euploidy (abnormal chromosom component)

Aneuploid abortion

~ 50% of clinically recognized pregnancy

loss

Autosomal trisomy → the first trimester

abortions + recurrent abortions.

Monosomy X (45/X) → compatible with live-

born females (Turner syndrome).

Triploidy → associated with hydropic placental

degeneration

Euploid abortion1. chromosomally normal abortuses → in late

pregnancy 2. incidence increased after maternal age of 35

years3. chromosomal structural abnormalities →

(translocations and inversions)isolated mutation or polygenic factorsvarious maternal factorspaternal factors (chromosome translocation in sperm

IV. Endocrine causes

Disturbances in the secretions of reproductive hormones → abnormal trophoblastic function

1.Luteal phase deficiency (LPD) - inadequate progesterone effect on the endometrium - 35% of recurrent pregnancy loss

2.Combined deficiency of E and P → the most common cause

3.Other forms: isolated E insufficiency, isolated P insufficiency, hyperandrogenism

V. Immunological causes

Autoimmune mechanisms antiphospholipid antibodies anticardiolipin antibodies

against platelets and vascular endothelium

vascular damage thrombosis placental destruction

abortion

V. Immunological abortions

Alloimmune mechanisms

The human embryo → an allogenic transplant that is

tolerated / facilitated by the mother.

Several immunological mechanisms - to prevent

fetal rejection:

- histocompatibility factors CMH, HLA-G

- circulating blocking factors

- local supressor factors

- maternal or antipaternal anti-

leukocytotoxic antibodies

VI. Maternal systemic conditions

1. endocrine disorders

2. blood group incompatibility (ABO, Rh)

3. toxic factors (cocaine, alcohol, cigarette smoking)

4. psychic or emotional causes, advanced maternal age, poor socio economic status, protein and vitamin under-nutrition

5. Cardio-vascular-renal hypertensive disorders

Clinical stagesA. Threatened abortion

Symptoms - bleedingspotting of bright blood

dark brown discharge

- cramping pain

- no changes in the cervix Usually, bleeding begins first and cramping abdominal pain follows (hours to several days). Differential diagnosis - ectopic pregnancy - dysfunctional uterine bleeding - uterine fibro-myomas - hydatidiform mole - benign lesions / invasive cancer

Clinical stages B. Inevitable abortion

Symptoms

- abdominal and back pain

- severe bleeding

- open cervixDuring first 2 months, abortion - 1 stage.

During the 2-nd trim., abortion - 2 stages:

1. rupture of the membranes + fetal expulsion;

2. incomplete expulsion of the placenta

Clinical stagesC. Incomplete abortion

In the majority of spontaneous abortions variable amounts of placental tissue may remain within the uterus (attached to the wall or lying free in the cavity). Bleeding - during or following abortion may be life-threateningprofuse → massive (→ hypovolemia)severepersistent

Sepsis - in cases with criminal or self- induced abortion.

Clinical stagesD. Missed abortion

retention of dead conceptus in utero for several weeks

E. Complete abortion

the uterus empties itself completely (fetus, fetal membranes, the placenta, the

decidua). This is possible only during the first 6 weeks.

Avortul – forme clinice

Treatment

accurate evaluation

1.pelvic examination visual and digital examination

of the cervix + bimanual palpation of the uterus and

of the adnexa.

2.the degree of cervical effacement and dilation -

determined by palpation.

3.Ultrasonic scanning (a normal-appearing sac+

normal embryo/fetus - favorable prognosis).

4.Serial beta-HCG

TreatmentThreatened abortion → treated at home / hospitalized.

Medical treatment - progesterone / synthetic progestational agents, i.m. or orally.

Inevitable abortion → surgical uterine evacuation (with suction technique or surgical procedure) + reducing blood loss and pain.

Incomplete abortion → surgical uterine evacuation because of the risk of infection and/or continued and excessive bleeding.

Missed abortion → surgical uterine evacuation Infected abortion → the operation should be delayed,

unless excessive uncontrolled blood loss, and antibiotics are administered.

TreatmentCervical incompetence → CERCLAGE

= surgical treatment, consisting of reinforcement of the cervix by some type of purse string stitches; best performed after the first trimester (14 weeks) but before cervical dilatation of 2 to 3 cm is reached.

Bleeding, uterine contractions or ruptured membranes are contraindications to this surgery.

The Mc Donald procedure = suture of monofilament placed in the cervix to encircle the internal os (less traumatic with reduced blood loss).

INCOMPETENT CERVIX

TreatmentAsherman syndrome treatment = lysis of

the adhesions via hysteroscopy and placement of an IUD to prevent recurrence of synechiae. Continuous high-dose estrogen therapy for 60 to 90 days.

Lupus erythematosus - Successful pregnancies with low-dose aspirin (inhibit thromboxane production by damaged platelets and endothelium).

Antiphospholipid syndrome – Heparin (to inhibit thrombosis) + corticosteroids (to suppress antibodies as well as to inhibit their action on target antigen).

Immunotherapy - highly controversial.