“Alexa, ask BabyMed”

Then:

I am trying to get pregnant

• Set my last period and my cycle length between 21 and 35 days)
• When is my next expected period?
• When are my fertile days?
• When is ovulation expected?
• When will my pregnancy test be positive?
• When is my due date?

I am pregnant

• If pregnant "set my due date"
• How far along am I?
• How many weeks pregnant am I today?
• How many weeks on xx/xx/xx
• How many more days to my due date?
• How many more weeks to my due date?
• Give me regular updates

Others have similar Alexa skills  but too simple

• Alexa skills pregnancy
• Alexa skills fertility

My Babymed – a skill for Amazon’s Alexa Voice Service, and the newest way for parents trying to get pregnant and those already pregnant to get the best information. 

It's a voice-activated tool (or Alexa "skill") that tells you about your pregnancy. Every time you use My Babymed, you’ll get a card in your Alexa app that shows you the info you just heard and a stunning 3-D fetal development image, plus links to more resources.
How do I start My Babymed?
There are two ways to launch My Babymed. You can:
• Go to the Skills section of your Alexa app, find "Babymed", and click "Enable Skill." Then tell Alexa, "Start Babymed.”
• Or simply say, “Alexa, enable the Babymed skill."
You'll be prompted whether you are trying to get pregnant or if you are already pregnant. State your last period or your due date, and you're off! Babymed will also calculate the due date and many other important fertility and pregnancy dates.

Alexa Skills Kit