Week 10: The Genetic Testing Decision

The Quick Brief

Your baby is now the size of a strawberry, and something remarkable has happened: fingers and toes are fully formed, and fingernails are starting to develop. The bones are beginning to harden from soft cartilage. But this week's main task for you isn't developmental—it's decisional. Genetic testing options are now available, and understanding what they can (and can't) tell you requires some homework.

What's Happening with Baby

At week 10, your baby measures about 1.2 inches—roughly the size of a strawberry. The embryo officially became a fetus around week 9-10, marking the transition from organ formation to organ maturation.

Key developments this week: arms, hands, fingers, feet, and toes are fully formed—no more webbing. Fingernails and toenails are beginning to develop. Bones are hardening from soft cartilage, though the skeleton won't fully ossify until after birth. The external ears are taking shape, moving from the neck toward their final position. External genitals are beginning to form, though it's too early to determine sex via ultrasound.

The fetus can now move its arms and legs, opening and closing its fists, though these movements are too small to feel. The brain is producing neurons at an astounding rate—on average, roughly 250,000 per minute. All major organs are present and beginning to function. The liver is producing bile. The kidneys are starting to produce urine.

What's Happening with Mom

The good news: for many women, nausea begins to decrease somewhere between weeks 10-14. The challenging news: it's not a switch that flips overnight. HCG levels peak around weeks 8-11 and then begin a gradual decline for the remainder of pregnancy. As hormone levels stabilize, symptoms often improve.

Round ligament pain may begin around this time. The round ligaments support the uterus; as the uterus expands, these ligaments stretch, causing sharp or aching pain in the lower abdomen or groin. It's usually harmless but can be startling. Sudden movements, sneezing, or laughing can trigger it.

Blood volume continues to increase, which can cause visible veins, especially on the breasts and abdomen. Some women notice their waistbands getting tighter—the uterus is now about the size of an orange. Visible baby bump typically comes later, but clothes may fit differently.

What Dad Should Do This Week

1. Research genetic testing options together

This is a decision that belongs to both of you. Here's what you need to know:

NIPT (Noninvasive Prenatal Testing):

• Available from week 10 onward
• Simple blood draw from mom—no risk to the pregnancy
• Screens for chromosomal conditions: Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patau syndrome (trisomy 13)
• Also reveals fetal sex with high accuracy
• Detection rate: about 99% for Down syndrome
• Important: NIPT is a screening test, not a diagnostic test. A positive result indicates increased risk, not certainty. Diagnostic confirmation requires CVS or amniocentesis.

First Trimester Screening (FTS):

• Combines blood test with nuchal translucency ultrasound
• Done between weeks 11-14
• Screens for similar conditions but with a lower detection rate (roughly 85-96% for Down syndrome, depending on timing)
• Lower cost than NIPT in many cases

Diagnostic Tests (CVS, Amniocentesis):

• Definitive diagnosis, not screening
• CVS (chorionic villus sampling): week 10-13
• Amniocentesis: week 15+
• Both carry small procedural risks
• Usually recommended only after positive screening results

Questions to discuss: Do we want screening information? How would a positive result affect our decisions? Is not knowing preferable to knowing? There's no universally correct answer.

2. Understand your insurance coverage for genetic testing

NIPT costs $500-$2,000+ without insurance. Coverage varies widely. Call your insurance before the test and ask specifically: Is NIPT covered? Are there criteria for coverage (maternal age, risk factors)? What's the out-of-pocket maximum? Some labs offer self-pay options around $200-300 regardless of insurance status—sometimes cheaper than going through insurance.

3. Conduct a finance audit

Pregnancy is expensive, and so is having a baby. This is a good week to: review your health insurance deductible and out-of-pocket max, calculate expected delivery costs (varies enormously by hospital and delivery type), start a baby fund if you haven't, and review your budget for flexibility. Knowing your financial situation now prevents surprises later.

4. Research parental leave policies

Check both your employer's policies. Many dads are surprised to learn they have paternity leave available. Even if unpaid, knowing your options allows you to plan. If you're considering taking leave, having an early conversation with your manager demonstrates responsibility, not weakness.

The Relationship Check-In

Genetic testing decisions can surface different values and anxieties between partners. You might feel differently about risk tolerance, the importance of information, or what you'd do with results. This is normal. The goal isn't to think identically—it's to understand each other's perspective and make a decision you can both live with.

She’ll sleep a lot in the first trimester. Some women also develop intense food and smell aversions. One dad’s friend’s wife developed a permanent aversion to the smell of onions during pregnancy — and it never went away. If she suddenly can’t stand your favorite meal, eat it outside the house. Don’t argue about it. It’s hormonal and involuntary.

Have the conversation before the test is offered at an appointment. Rushed waiting-room decisions are rarely good decisions. Ask each other: What information do we want? What would we do with concerning results? What feels right for our family?

What's Coming Up

Week 12 is a significant milestone: miscarriage risk drops considerably, and many couples choose to announce their pregnancy more broadly. Before then, you'll want genetic testing decisions made and potentially completed. The first trimester screening window closes at week 14, so don't delay if you want that option. Also start thinking about: when and how to announce publicly, maternity leave planning, and whether you'll need to address childcare or housing changes.

Quick Reference Box

• Baby size: Strawberry (~1.2 inches)
• Key milestone: Bones hardening, external genitals forming, NIPT testing available
• Dad priority: Research and discuss genetic testing options
• Source: Cleveland Clinic NIPT Testing, Johns Hopkins First Trimester Screening

Sources:

• Cleveland Clinic: NIPT Test (Noninvasive Prenatal Testing)
• Johns Hopkins Medicine: First Trimester Screening, Nuchal Translucency and NIPT
• UT Southwestern: What Noninvasive Prenatal Testing Can Tell You