MULTIPLE PREGNANCIES

When more than one fetus develops in the uterus it is called multiple pregnancy. Simultaneous development of Two fetuses – Twins Three fetuses – Triplets Four fetuses – Quadruplets Five fetuses – Quintuplets Six fetuses - Sixtuplets

Twins It is the commonest variety of multiple pregnancy. It can be Dizygotic twins – 2/3 Monozygotic twins – 1/3 Twins resulting from fertilization of two ova during a single ovarian cycle are called as DIZYGOTIC TWINS. (fraternal, binovular)

Monozygotic twins (identical, uniovular) Twins arise from a single fertilized ovum that subsequently divides into two similar structures each with the potential for developing into a separate individual. The process of monozygotic twinning is in a sense a teratogenic event and monozygotic twins have an increased incidence of discordant malformations. The division of the fertilized ovum may result from a delay in the timing of the normal developmental events. Delayed ovum transport through the tubes increases the risk of twinning - because progestational agents, O.C. Pills decreases the tubal motility, delay tubal transport and implantation. They are believed to increase the risk of twinning in pregnancies conceived in close temporal proximity to contraceptive use. Minor trauma to the blastocyst during Assisted Reproductive Techniques( ART ) may possibly lead to increased incidence of twinning. INCIDENCE OF MONOZYGOTIC TWINS IS 1 : 250 BIRTHS

Prevalence of Dizygotic Twins: a) Race – Highest among Negroes Lowest among Mongols b) Heredity – More transmitted through the female (Maternal side) c) Age – Maximum between the ages of 30 to 37 years d) Parity – Incidence increases from fifth gravida (6.6%) e) Nutritional – Taller , heavier women have 25% to 30 % greater twinning rate than shorter nutritionally deprived women f) Iatrogenic – Drugs used to treat infertility - Clomiphen Citrate ( 5%-6%) - Gonadotrophin theraphy(20%-40%)

Physical changes in Mother Excess than that is seen in singleton pregnancy. There is an increased weight gain and increased cardiac output (20%) Plasma volume is increased and there is no equivalent increase in red cell volume resulting in exaggerated hemodilution and anaemia. The uterus and non-fetal contents may achieve a volume of 10 liters or more and weigh excess especially in monozygotic twins leading to acute hydramnios.

Patient may present as Advanced Maternal age High parity Exaggerated pregnancy symptoms like nausea and vomiting due to increased HCG levels Unusual enlargement (distension) of the uterus In multi-intelligent mother may notice increased fetal movements In the later months of pregnancy, patient presents with cardio – respiratory embracement which is evident as palpitations, shortness of breath Due to the pressure of the enlarged uterus over the veins swelling of the limbs varicose veins and even hemorroids may be present. Symptoms of anemia Patient may be asymptomatic and present as preterm labour with undiagnosed twins.

History of Ovulation inducing drugs Family history of twinning In multi fetal gestations complicated by hydramnios – renal function may be seriously impaired due to obstructive uropathy

G.P.E . Usually multi, with high parity, tall women Anemia Pedal oedema Evidence of preecclampsia (25%) Weight gain during each visit is more than expected

Abdominal examination Inspection: Abdomen is unduly enlarged with barrel shape May be associated with hydramnios (10%) with tense shiny skin over the abdomen Palpation: Height of uterus is more than the period of amenorrhoea which is evident from mid trimester Girth of the abdomen is more Multiple fetal parts can be felt Fetal bulk seems disproportionately larger to the size of the fetal head. Finding of two fetal heads or three fetal poles is diagnostic Hydramnios (10%) is common in monozygotic twins . This is due to the increased renal perfusion with increased urinary output which accompanies the hypervolumia of larger twin. Malpresentations: Usual presentations are Both vertex 60% First vertex and second breech 20% First breech and second vertex 10% Both breech 10% First vertex and second transverse rare Lastly both transverse - conjoined twins to be ruled out Placenta previa: due to bigger size of placenta Auscultation: Simultaneous hearing of two distinct heart sounds located at separate spots with a silent area in between by two observers provided the difference in heart rate is at least 10 beats/min

Internal examination: One head may be felt deep in pelvis and other is located by abdominal examination Patient may present with preterm labour