OSCE stations: Answers

Chapter 6

In this scenario, a pregnant woman of unstated gestational age is presenting for a booking visit. The woman is obese, is on treatment for hypertension and is taking high-dose folic acid. She is living with her husband with no mention of children. She is positive for glycosuria, which is a distractor.

You should establish from the history the gestational age, the details of her two past pregnancies, history of familial or inheritable disorders, general medical and surgical history and progress to date in the current pregnancy. Include open questions regarding any concerns the patient might have.

Treated hypertension is a key feature in this case. Establish how long the woman has been taking atenolol, the underlying cause of hypertension, if known, and what her recent blood measurements have been. Enquire regarding symptoms of poorly controlled hypertension, and consider pre-eclampsia if the gestational age is 20 weeks or more.

The second key feature is that the woman is taking high-dose folic acid. Ask her why she is taking this high dose. It might be related to neural tube defect in a previous pregnancy. Or it could indicate a thrombophilia.

The third key feature is that the woman is obese. This increases her risk of pregnancy complications, including gestational diabetes. Glycosuria is a distractor. Nevertheless, consider what screening or diagnostic tests for gestational diabetes and other pregnancy complications (pre-eclampsia, fetal anomalies, perturbation in fetal growth) are appropriate.

Synthesize the data you have acquired and explain to the actor your working diagnosis/diagnoses and plans for management. In addition to screening and/or diagnostic tests, this case is high risk and requires specialist management per local protocols.

Finally, be prepared for simple questions from the actor. These could be for clarification of diagnosis and management, safety of atenolol in pregnancy or related to a social issue such as appropriateness of her continuing to work full time in a stressful occupation.

Chapter 7

In this scenario, a woman is enquiring about adjustments during her pregnancy that she should make to her diet and exercise routine. The woman is overweight, has polycystic ovarian syndrome and has successfully lost weight through changes to her diet and with exercise.

The key requirements are to establish what her current diet and exercise habits are. This should include open questions regarding any concerns the woman has.

Evidence regarding what constitutes an adequate diet in pregnancy is limited in part due to the retrospective nature of most studies and the wide range of diets people have. However, some generalizations are likely to apply to your locale, including recommendations for routine pre-pregnancy supplementation with folic acid and routine antenatal supplementation with oral Fe regimens. A diet that consists largely of junk food and soft drinks increases the risk of pre-eclampsia and gestational diabetes. Other dietary factors include inadequate calcium and iodine intake (e.g. by avoidance of dairy foods and iodized salt). Some vegetarians might, without dietary supplementation, have inadequate vitamin B ₁₂ intake. The woman’s occupation creates opportunities for overeating. Estimation of daily calorie intake should be covered in the enquiry.

In addition, enquire about intake of relevant non-food substances, including alcohol and cigarettes, and consider whether she has adequate sun exposure for sufficient vitamin D production.

Exercise in pregnancy appears to limit excessive weight gain, and aerobic exercise maintains or improves fitness. Exercise in combination with diet appears to reduce the risk of gestational diabetes and caesarean delivery. Unfortunately, there is insufficient evidence to tailor this general information to an individual’s diet and exercise habits. However, there are pragmatic considerations, for example, does the woman have an existing condition such as low back pain or joint pain that might be exacerbated during pregnancy and impact her ability to exercise? If so, how would you address that in relation to her recommended calorie intake?

Be prepared to answer questions such as ‘Should I eat for two?’ ‘Will continuing with my daily gym circuit harm the baby or bring labour on early?’ and ‘What exercises can I do later in pregnancy?’

Chapter 8

In this scenario, a woman in her second pregnancy presents with a third-trimester antepartum haemorrhage. The woman has been triaged by a midwife. She is clinically stable, the fetal heart rate is normal, abdomen soft and symphysial–fundal height is consistent with dates and with a breech presentation. The haematuria is likely explained by contamination of the sample.

Begin by forming an impression of the patient’s state both physically and mentally by ‘end of the bed’ observations. Although this is not a real encounter, be alert to cues from the actor that might suggest the situation is more acute than indicated by the observations provided.

From your history, establish the onset and nature of the bleeding, associated or precipitating factors and whether this is the first or a recurrent episode. Antepartum haemorrhage is conventionally categorized as painful (suggesting placental abruption and/or pre-term labour) or painless (suggesting placenta praevia or a local cause of bleeding). Confirming dates is critical, as is enquiring about prior investigations such as previous placental location by ultrasound, and blood group and antibody status. The obstetric history must also be established. If the patient has had a prior lower segment caesarean delivery, consider placenta praevia accreta.

The next steps include repeating the abdominal examination, performing a speculum examination and arranging in the unit a cardiotograph (CTG) and relevant blood tests. It would be prudent also to request a formal urine microscopy and culture. Most acute assessment units will have a portable ultrasound, and this would be used to check the presentation and placental localization. All of this should be explained to the actor in clear lay terms. Include in your explanation the reasons for performing the additional examination and tests, i.e. say what you are looking to find or exclude. Local protocol might include that this patient be offered betamethasone and likely will require her to be observed for a minimum period either in the assessment unit or admitted to the ward. However, as this is a high-risk situation, you should indicate that the patient will also be reviewed by a senior member of the medical staff.

Finally, the patient will be anxious about the bleeding and, if she has a child at home, about arrangements for that child’s care whilst she remains under observation. In relation to fetal safety, cautious reassurance is appropriate whilst recognizing this is an unpredictable situation that might yet result in pre-term operative delivery. It is not safe at present for the woman to leave hospital, so child care arrangements will need to be made with that in mind.

Chapter 9

In this scenario, a woman with one child and two pregnancy losses is attending for prenatal counselling. She has thrombophilia (homozygous factor V Leiden), has been taking warfarin ‘for several years’ and is normotensive. She might have had recurrent thromboembolism.

As this is a prenatal presentation, establish what the woman’s plans are. When does she want to become pregnant? The couple are probably using either barrier contraception or a levonorgestrel intrauterine system. Are there subfertility problems that need to be addressed? Are there any other health problems in the woman or in the family history that also must be considered? Are her vaccinations up to date?

Warfarin is teratogenic and will need to be replaced with a safer anticoagulant, such as enoxaparin, prior to conception. The woman should be well informed about her thrombophilia and its management and might have used enoxaparin in her last pregnancy. Use open questions such as ‘Why you are taking warfarin?’ and ‘How was this problem managed in your last pregnancy?’ Establish in detail the obstetric history, being mindful of the association with early pregnancy loss and intrauterine growth restriction in such cases. Were there complications in the last pregnancy requiring early delivery? What was the birth weight? Is the child healthy?

As this is an advanced topic, the next step in management requires engagement of an obstetrician or a multidisciplinary team per local protocols. However, you should also indicate what you expect will be done, including a managed change in the anticoagulation regimen, plus routine preventive health care, such as updated vaccinations where required and supplements to minimize risk of neural tube defect.

The actor is likely to ask only for clarification of your proposed management if that is required.

Chapter 10

In this scenario, a woman at 34 weeks’ gestation (sure dates) and with limited antenatal care presents for a routine antenatal clinic review. There is a breech presentation and no change in the symphysial–fundal height in 4 weeks, suggesting intrauterine growth restriction (IUGR). The dates are accurate, and pre-eclampsia, although on the differential diagnosis of IUGR, appears unlikely in this case.

The history should be directed at establishing whether the woman has noticed anything wrong, enquiring about fetal movements and about risk factors for IUGR, including maternal smoking, chronic maternal disease, potentially harmful medications, results of screening for fetal anomalies, transplacental infection, antepartum haemorrhage and IUGR in previous pregnancies. Because time is short, the actor will be scripted to answer in the negative for most or all of these problems.

Prompt investigations are required to assess fetal wellbeing and rule in or rule out the provisional diagnosis. A CTG should be requested, as should formal ultrasound evaluation for assessment of fetal growth parameters, amniotic fluid volume and Doppler flow velocity (fetal umbilical artery plus or minus fetal middle cerebral artery per local protocol). Other investigations usually can be delayed pending these results. Explain the investigations – what they are and their purpose – using plain language.

You will then be provided with results in report form (some schools might expect you to interpret an unreported CTG). Explain your interpretation of these data to the actor. Conclude with an explanation of your management, including factoring in the significance of the breech presentation if confirmed. As this is a complicated case, input of an obstetrician is required.

The actor is likely to ask only for clarification of your proposed management.