For the broader O&G Magazine readership, balanced answers to those curly-yet-common questions in obstetrics and gynaecology.
The MBS Review and Choosing Wisely, have much in common: each has the objective of the best-possible patient care within the available resources of the health system. In both cases, it has been necessary to invoke the concept of ‘good-value care’. Does this test or treatment represent the best possible use of limited public-health funding?
Right at the heart of this concept of ‘good value care’ sits the routine pathology and imaging investigations requested in early pregnancy. Already the patient receives more from the MBS for pathology and imaging in the year of a pregnancy than she does for the clinical care received. It would not be too difficult to spen4d the entire obstetric budget on blood tests and imaging as the list with ‘some value’ is almost endless. It is not unusual for a patient to arrive for her first antenatal visit armed with an extensive, but quite bizarre, collection of ‘screening tests’ – usually still omitting some that are actually needed.
So what is a ‘good value’ test? In order to assess value, the following should be considered:
- Likelihood of a positive finding
- Severity of harm if not diagnosed
- Ability of any consequent therapy to avoid harm
- Other strategies that might be as good (or almost so) at lesser cost
Blood tests and an urine analysis
The following are generally agreed as routine antenatal blood tests at the first antenatal visit and are recommended in the College Guideline:
- Full blood examination
- Blood group and antibody screen
- Serology for: rubella, varicella (in absence of known immunity), hepatitis B, hepatitis C, HIV and syphilis
- Midstream urine urinalysis for microscopy, culture and sensitivities
Syphilis testing is surprisingly controversial for some clinicians, but given that it is a very serious condition with an effective simple treatment, screening remains warranted despite its infrequency. Such is the broad acceptance of these tests that the MBS Review Obstetric Clinical Committee has advised that they be grouped together as a single MBS item: ‘routine early pregnancy tests’.
NIPT versus combined screening for chromosomal anomalies
This subject is beyond the scope of this article, but is extensively covered in RANZCOG Statements 35, 59 and 60. This is a particularly difficult area for the clinician because of the cost implications for the patient. MBS funding is urgently needed for non-invasive perinatal testing (NIPT), but may initially be ‘contingent’ on an elevated a priori risk by virtue of age or combined screening.
Screening for genetic carrier status
Genetic carrier status screening (for example, cystic fibrosis) is also difficult because of the cost to the patient that must be weighed against a low, but very significant, risk. These are decisions for the patient to make and all need to be aware of the availability of these tests. Frequently, the patient will look to the clinician for advice, ‘What would you do, doctor?’ The honest answer may be, ‘That would depend on how much money I have.’
Mid-trimester ‘morphology’ scan
A referred ultrasound is indicated for the 20-week ‘morphology’ scan. Cervical length assessment is now routinely recommended at the time of the mid-trimester morphology ultrasound (RANZCOG Statement C-Obs-61).
Tests that should not be ‘routine’
Vitamin D, TSH, ferritin and other biochemical tests
Vitamin D is an expensive test for the taxpayer; many millions for low benefit. Although minor degrees of deficiency are very common, few will have seriously low vitamin D levels that lead to clinical complications. Only those at high risk for serious deficiency should be tested. Similarly, routine screening for thyroid disease cannot be regarded as ‘good-value care’ on current evidence and is not recommended. Ferritin testing also should not be performed routinely, but is recommended where there is a high risk of deficiency.
The list of other biochemical tests that are sometimes performed is extraordinary. Can any medical practitioner genuinely believe that routine urea and electrolytes, liver function tests, cholesterol or lipids represent good-value care for the taxpayer?
Serology for parvovirus (B19), cytomegalovirus, toxoplasmosis and other serology
Screening for parvovirus, cytomegalovirus (CMV) and toxoplasmosis is only indicated if there are specific indications in pregnancy and should not be performed as a routine. A prominent obstetrician informed me, ‘I like to know if they are parvovirus immune so I can reassure them immediately later in pregnancy if they phone me after contact with a child with slapped cheek, without having to test then.’ Good-value care? I think not. CMV causes long term sequelae for 1 in 1000 Australian children. Diagnosis can be difficult and treatment controversial. An effective CMV vaccine is urgently needed but population screening is not currently recommended. Routine testing for toxoplasmosis is appropriate in areas of high incidence (for example, France) but the incidence is much too low in Australia to represent good-value care. Routine screening by serology for other infections in early pregnancy is not indicated and wastes precious health resources.
Referred ‘dating’ ultrasounds in the first trimester
Point-of-care ultrasound (performed within the GP or specialist obstetrician’s rooms or clinic) will usually be sufficient to confirm viability and date a first trimester pregnancy. Where the point-of-care ultrasound is technically difficult or produces uncertain results, a referred ultrasound is appropriate. Point-of-care ultrasound in pregnancy is often particularly ‘good-value care’ and it is inexplicable that it is currently so poorly funded.
RANZCOG. Routine antenatal assessment in the absence of pregnancy complications. C-Obs 3(b). 2015. Available from: www.ranzcog.edu.au/Statements-Guidelines.
National Antenatal Care Guidelines. Department of Health. 2012. Available from: www.health.gov.au/internet/main/publishing.nsf/Content/6E83884557AB0AF5CA258110001BC9F9/$File/ANC_Guidelines_Mod1_v32.pdf.
RANZCOG. Screening in Early Pregnancy for Adverse Perinatal Outcomes. C-Obs 61. 2015. Available from: www.ranzcog.edu.au/Statements-Guidelines.
RANZCOG. Vitamin and mineral supplementation and pregnancy. C-Obs 25. 2015. Available from: www.ranzcog.edu.au/Statements-Guidelines.
Lazarus JH, Bestwick JP, Channon S, et al. Antenatal thyroid screening and childhood cognitive function. N Engl J Med. 2012;366(6):493-501.
The American College of Obstetricians and Gynecologists. Thyroid disease in pregnancy. Practice Bulletin Number 148. Obstetrics & Gynecology. 2015;125(4):996-1005.
Testing for hypothyroidism during pregnancy with serum TSH. C-Obs 46 2015. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.
The American College of Obstetricians and Gynecologists. Cytomegalovirus, parvovirus B19, varicella zoster, and toxoplasmosis in pregnancy. Practice Bulletin Number 151. Obstetrics & Gynecology. 2015;125(6):1510-25.
Society for Maternal-Fetal Medicine (SMFM), Hughes BL, Gyamfi-Bannerman C. Diagnosis and antenatal management of congenital cytomegalovirus infection. Am J Obstet Gynecol. 2016;214(6):B5-B11. 3.
Salomon LJ, Alfirevic Z, Bilardo CM, et al. ISUOG Practice Guidelines: performance of first-trimester fetal ultrasound scan. Ultrasound Obstet Gynecol. 2013;41:102-13.