From the Guidelines
At 7 weeks pregnant, it is essential to schedule a transvaginal ultrasound (TVUS) to confirm the pregnancy, visualize the gestational sac, yolk sac, and embryo, and assess cardiac activity, as recommended by the Society of Radiologists in Ultrasound consensus conference 1.
Key Developments at 7 Weeks
- The embryo is approximately 10-12 mm in length, and its greatest dimension can be measured using crown-rump length (CRL) for dating purposes 1.
- The yolk sac is visible on TVUS, confirming a definite gestational sac/pregnancy, and is typically ≥ 6 mm in diameter 1.
- Cardiac activity can be detected on TVUS at this stage, and rhythmic pulsations in the embryo should be reported as cardiac activity or cardiac motion, avoiding terms like 'heart motion' or 'heartbeat' 1.
- The amnion, a thin membrane surrounding the embryo, can be visualized on TVUS at around 7 weeks gestational age, and the amniotic cavity is the fluid-filled space contained by the amnion 1.
Recommendations
- Take a prenatal vitamin containing at least 400mcg of folic acid to prevent neural tube defects.
- Avoid alcohol, tobacco, and limit caffeine to less than 200mg daily.
- Stay hydrated and try eating small, frequent meals if experiencing nausea.
- Schedule the first prenatal appointment to monitor health and baby's development, as the first trimester is critical for organ development.
- A TVUS between 8-12 weeks will confirm the pregnancy, check the heartbeat, and establish the due date more precisely, as per the American Institute of Ultrasound in Medicine practice parameters 1.
From the Research
Pregnancy and Nausea
- At 7 weeks pregnant, nausea and vomiting are common symptoms experienced by many women 2
- A study comparing pyridoxine and doxylamine succinate-pyridoxine HCl for nausea and vomiting of pregnancy found that doxylamine succinate-pyridoxine HCl was more effective in reducing symptoms, especially in women with more severe symptoms 2
Prenatal Exposure to Teratogenic Medications
- Prenatal exposure to teratogenic medications is a significant concern, and the US Food and Drug Administration has implemented Risk Evaluation and Mitigation Strategies to prevent such exposures 3
- A study found that prenatal exposures to definite teratogens decreased slightly between 2006 and 2017, while exposure to potential teratogens increased 3
Dos and Don'ts in Pregnancy
- Pregnant women need to be aware of what they should and should not do to minimize risk and optimize outcomes, and evidence-based recommendations are essential 4
- However, there is no specific information available in the provided studies regarding the 7th week of pregnancy
Hypertension and Pregnancy
- Methyldopa is a centrally acting antihypertensive agent that has been used to treat hypertension, including in pregnant women 5
- Vitamin B6, including pyridoxine, has been found to have antihypertensive and neuroprotective actions, and may be beneficial in reducing blood pressure and protecting against neurotoxicity 6