Pregnancy Ultrasound scans can confirm a live intrauterine pregnancy almost from week 5 (one week after the missed period). We would recommend a dating ultrasound scan at 8-9 week in uncomplicated pregnancies. This is the best time to date a pregnancy with an accuracy of 3-4 days. It offers a peace of mind for the parents as the blue line on the pregnancy test now materializes to a developing baby with a visible heart beat.
Unfortunately a large number of pregnancies (up to 10%) fail during the first few weeks. Furthermore with the increase of sexually transmitted diseases (STDs) in particular Chlamydia, more women are susceptible to fallopian tube damage and consequently have a higher risk of an ectopic pregnancy.
Having a readily available service that will combine high level of scanning expertise, combined with clinical knowledge (that allows to interpret the history and understand the management options) is an absolute must for any unit that offers acute Obstetric & Gynecology cover.
We collaborate with excellent laparoscopic surgeons who will be able to deal with potentially life threatening ectopic pregnancies early with minimum possible inpatient hospital stay.
At 12-13 weeks most of the main structures of the baby have formed allowing an initial anatomical survey to be performed. At this stage, many gross anatomical problems can be picked up by an early detailed pregnancy ultrasound scan. Typical examples are acrania (when the upper part of the baby’s skull and brain have not developed), omphalocele and gastroschisis (when the anterior abdominal wall has not developed properly). Pregnancy ultrasound scan helps diagnosing these problems in the first trimester the parents have the opportunity very early in the pregnancy to decide how they would like to continue with their pregnancy and seek appropriate care.
This will constitute a major part of the service we will be offering. It will be a combined effort from our lab our physicians and the Fetal Medicine unit.
Traditionally the age of 35 was quoted as the cut off time for offering an invasive test like amniocentesis. Such an approach would only pick up about 40% of babies with Down’s while you would have to test about 15% of pregnant mothers. This anachronistic approach has been replaced by tests that utilize a series of ultrasound and biochemical markers. The one most widely known is the Nuchal Translucency (the thickness at the back of the baby’s neck). These ultrasound measurements combined with the mother’s age and a set of blood test can pick up to 95% of babies with Trisomy 21 for a 5% false positive rate.
Our aim is to introduce a multi step approach to fully cover mothers who would like to opt in for screening.
Counseling and Blood tests at 10/40 at the time of a viability scan.
NT / Nasal bone scan at 12/40 combined risk calculation.
Counseling Bloods tests and Scan all done at 11-13 weeks. The parents are informed of the NT result. A numerical risk calculation is given a few days later using the blood results as well.
For those parents who have booked late (after 13/40). Second trimester biochemistry (quadruplet test).
Pretest counseling; Whenever a screening test is offered it is imperative that this is done with the appropriate counseling to ensure the parents are fully informed and the test is the right test for their family structure and ethical beliefs.
Posttest counseling; When a screening test is offered inevitably at least 5% of the clients screened will be positive. The provider has to have in place a care pathway to deal with these parents swiftly as they will be experiencing extreme anxiety after a positive result.
This is the next step for those with positive results. We will be offering the full range of diagnostic procedures for those parents where the results came as positive including CVS and amniocentesis. With the current techniques available they can have a result in 3-4 days.
At 19-22 weeks most of the fetal organs are in an advanced stage of development. A detailed pregnancy ultrasound scan at this stage can pick up a large number of significant structural anomalies that can affect the child’s life and development. It is recommended that all pregnancies should have an anomaly pregnancy ultrasound scan performed by an appropriately trained professional.
It is imperative for those who offer an anomaly pregnancy ultrasound scan to have in place a system for the management of the cases with proven or suspected anomalies. From the moment a concern is raised with the parents about their baby it is critical to be able to offer professional counselling that will cover; 1. What are the implications for the baby, short and long term, 2 What are the implications for the antenatal care/delivery/ postnatal care. 3. What are the additional investigations or treatments that may be needed. 4. the multi professional care needed for these pregnancies.
Preterm labour remains the single largest factor for neonatal morbidity and mortality. Traditional teaching indicates that the mother’s previous history is a strong predictive factor for preterm labour. Although this is true, most preterm deliveries happen in women without prior history. A single pregnancy ultrasound scan for cervical measurement (measuring the length of the neck of the womb) at about 22 weeks can predict the majority of preterm births between weeks 24- 30. This is the most important time as delivery at that stage of the pregnancy has the biggest impact in survival and subsequent morbidity.
Women who had a premature labour in the past are at high risk of having the same complication in future pregnancies. Blanket interventions like a cervical suture have been proven to be ineffective and can have serious complications. Serial pregnancy ultrasound scans to measure the cervix from 13-26 weeks can offer to the mother and the caring physician the much needed reassurance. Furthermore they can select with good accuracy the group of mothers where further intervention is needed.
Both pre-eclampsia and IUGR can have devastating consequences for mother and baby. Placental dysfunction plays a central role in the development of both these major obstetric complications. Measuring by a pregnancy ultrasound scan the flow in the uterine arteries during the second trimester and more recently in the first trimester has been proposed as an effective screening test. The advantages of screening are reassurance for those who are screen negative. For those who are found to be at increased risk it indicates the initiation of a close surveillance programme in order to prevent more serious complications like eclampsia and fetal death.
Examination of the fetal heart is the one of the most challenging parts of pregnancy ultrasound scanning. Even in countries with well developed ultrasound services like the UK only 60-70% of major anomalies are picked up. Certain groups of mothers are at an increase risk for cardiac anomalies. For example where the risk for serious structural cardiac anomalies in the general population is 0.1-0.5% in diabetic mothers this risk is 2%. Targeted pregnancy ultrasound scan offering detailed examination in these cases can dramatically increase pick up rate of anomalies. These will reassure the majority of mothers while for those with problems it will allow the appropriate pregnancy planning to ensure the baby will have the best care when it is born.
These pregnancy ultrasound scans produce images or video that are easier for the parents to identify. Life like views of the baby in the womb are obtained and it is believed that this can aid the parental bonding with their unborn baby. 3D 4D scans can also show a benefit in selected fetal anomalies like cleft lip and palate.
These scans are mostly done in the third trimester of pregnancy. Their aim is to confirm that the baby is growing appropriately. They are of particular importance in those pregnancies that are complicated by conditions that can affect the baby’s growth like pre-eclampsia or diabetes. Mothers whose previous pregnancies have been complicated by growth retardation (small baby) would also benefit from detailed follow up of the fetal growth. Monitoring the fetal growth and the placental and fetal circulation allows the obstetric team to plan the best time for delivery balancing the risk of prematurity against a hostile intrauterine environment.
In certain cases the unborn baby is at risk of anemia (low blood count). Typical examples are Rh incompatibility and Parvovirus infection. In these cases the baby needs to followed up with a series of scans (Doppler of the Middle Cerebral Artery) that can detect early fetal anemia and allow appropriate pregnancy planning and if needed intervention.
Certain groups of pregnancies require close follow up with a number of ultrasound examinations. Furthermore, for many patients it is preferable to have a prearranged pregnancy ultrasound scan package for their pregnancy as it makes scheduling easier and it can be cost effective if discounts are offered.
The following are typical examples of pregnancy ultrasound scan care packages;
1. Serial cervical scans
Mothers at risk for preterm labor are advised to have serial measurements of the cervical length (the neck of the womb) this starts at 13-14 weeks and is done weekly / fortnightly till approximately 26 weeks.
2. Serial growth scans
Are recommended for pregnancies complicated by diabetes or pre-eclampsia.
3. Mother with diabetes pregnancy care package
Preconception clinic (before the couple tries to get pregnant. It allows risk assessment appropriate planning
13 weeks first trimester / screening
20 week / detailed echocardiography
24/28/30 and then every 2 weeks till delivery at 39 weeks.
4. Multiple pregnancies
These pregnancies are at high risk for a number of complications like preterm labour / growth retardation.
11-13 weeks – determine chorionicity/ first trimester screening
20 weeks anomaly
cervical length scan
Growth scans at 26 30 34 36 weeks.
In particular for monochorionic twins every 2 weeks from diagnosis. If there are signs of early TTS (twin to twin transfusion syndrome a unique complication that affects up to 20% of Monochorionic twin pregnancies) then weekly.