Atenolol and propranolol are associated with intrauterine growth retardation when used for prolonged periods during pregnancy. They are class D agents during pregnancy. Other beta-blockers may not share this risk.

Methyldopa, hydralazine, and calcium channel blockers have not been associated with intrauterine growth retardation. They are generally acceptable agents to use for established, significant hypertension during pregnancy.

Transportation of the maternal IgG through the placenta starts around the 12 week of gestation.

Bicornuate uterus is associated with an increased chance of urinary tract anomalies. Urinary tract anomalies were present in about 23.6% of cases of bicornuate uterus patients.

Invasive procedures as fetal scalp blood sampling or internal electrode and episiotomy increase vertical transmission of HCV, especially in patients with positive HCV RNA virus load at delivery that is why it should be avoided.

The luteinizing hormone (LH) surge during ovulation causes: Increases cAMP resulting in increased progesterone and PGF2 production PGF2 causes contraction of theca externa smooth muscle cells resulting in rupture of the mature oocyte

Medical abortion is preferred from 4 to 9 weeks of gestation and in Australia, suction curettage is the most frequently used method of abortion as it is considered useful from 6 to 14 weeks of gestation.

Mifepristone is a synthetic anti-progesterone, which is found to be effective for abortion when combined with misoprostol. There are evidences which suggest the effectiveness of misoprostol and mifepristone in both first and second trimesters. It is most commonly administered as a single dose of mifepristone followed by misoprostol, a prostaglandin, given orally or vaginally two days later. Prostaglandin can be repeated at an interval of 4 hours if required.
As the vaginal use shows only few gastrointestinal side effects Misoprostol is more effective and better tolerated vaginally than orally. Misoprostol is not approved for its use in termination of pregnancy, but is available in the market due to its indications in other conditions.
Methotrexate can be used orally or as an intramuscular injection followed by misoprostol up to seven days later, but this also is not a preferred method for termination of pregnancy in Australia.

Ultrasound findings in early pregnancy can help determine the viability of an intrauterine pregnancy. In the absence of a fetal heartbeat and no visible fetal pole, the mean gestational sac diameter should be measured. A sac diameter of less than 25mm on a transvaginal ultrasound scan is likely an indication of a miscarriage. In the presence of a fetal heartbeat, the crown-rump length should be less than 7mm according to NICE guidelines. Further scans are indicated 14 days later to confirm the diagnosis. The diagnosis of ‘pregnancy of uncertain viability’ is given in situations where there is inadequate ultrasound evidence to diagnose a miscarriage, such as a developing sac but no visualisation of a foetus with a heartbeat.
Ultrasound findings for partial molar pregnancy are an enlarged placenta with multiple diffuse anechogenic patches, while findings in a complete molar pregnancy include an enlarged uterus with multiple small anechogenic spaces (snowstorm appearance), or the bunch of grapes sign representing hydropic trophoblastic villi.

After the release of the oocyte, the theca and the granulosa cells form the corpus luteum which undergoes extensive vascularization for continued steroidogenesis. Progesterone is secreted by the luteal cells and is synthesized from cholesterol. The luteal phase lasts for 14 days and if implantation does not occurs the corpus luteum starts to degenerate. As B-HCG produced by the implanted embryo maintains it and without it luteolysis occurs.

Twin gestations are generally at increased risk of complications and this risk is further stratified based on the chorionicity ie. number of placentas and amnionicity, the number of amniotic sacs of the gestation. In the given case patient has monochorionic diamniotic twins, which means 1 placenta and 2 amniotic sacs, based on the presence of 2 embryos, a single placenta and a thin intertwin membrane composed of 2 amniotic sacs that meets the placenta at a 90-degree angle (“T sign”). In patients who appear to have a single placenta, the base shape of the intertwin membrane distinguishes between a monochorionic (“T sign”) and fused dichorionic (“lambda sign”) gestation.
Monochorionic twins are at high risk for twin-twin transfusion syndrome (TTTS), which is a complication that can result in heart failure and fetal
eonatal mortality in both twins. In TTTS, unbalanced arteriovenous anastomoses are present between the shared placental vessels that supply the twins, because of these anastomoses, blood from the placental arteries from one twin (donor), which is of high resistance/pressure, is shunted into the placental veins of the other twin (recipient) with low resistance/pressure. This shunting of blood away from the donor twin causes anemia that leads to renal failure, oligohydramnios, low-output heart failure, and fetal growth restriction. In contrast, the shunting of blood toward the recipient twin causes polycythemia, which leads to polyhydramnios, cardiomegaly, high-output heart failure and hydrops fetalis. This in turn makes both twins at high risk for intrauterine and neonatal death.
Mild TTTS is expectantly managed with serial ultrasounds to evaluate for worsening clinical features, whereas moderate-to-severe cases are treated with laser coagulation of the placental anastomoses.

In monozygotic twins, placentation type is determined by timing of the twinning.  Twinning that occurs shortly after fertilization yields a dichorionic diamniotic gestation.  In contrast, the incomplete division (ie, fission) that can lead to conjoined twins occurs later in development and yields a monochorionic monoamniotic gestation. As the twins are in the same sac, monochorionic monoamniotic gestations can be complicated by cord entanglement but not possible in the given case as this patient has diamniotic twins.

Risk factors for placenta accreta, implantation of the placenta directly into the myometrium, include placenta previa and prior uterine surgeries like cesarean delivery, myomectomy, etc

Twin pregnancies are at increased risk of placenta previa (placental tissue that covers the internal cervical os); however, this patient has a fundal placenta, making this complication unlikely.

Monochorionic twin gestations can be complicated by twin-twin transfusion syndrome, which is potentially a fatal condition that results from unbalanced vascular anastomoses between the vessels supplying umbilical cords of each twin.

Glomerular filtration rate (GFR) rises immediately after conception and increases by about 50 per cent overall, reaching its maximum at the end of the first trimester. GFR then falls by about 20 per cent in the third trimester, returning to pre-pregnancy levels within 12 weeks of delivery.