regarding maternity leave benefits ("barselsdagpenge") there are two sets of rules depending on whether your work as freelancer is considered as "wage-earner" or "self-employed".
Barselsdagpenge is paid by "Udbetaling Danmark" (not the A-kasse), and Udbetaling Danmark will use the same guidelines as our Tax Authorities (skat.dk) do,
when assessing whether it is "wage-earner" or "self-employed".
If you work according to the employer's instructions, at its expense and risk, and as part of an agreement, then it will be considered as "wage-earner".
However I will recommend you to contact "Udbetaling Danmark" to find out how your freelance work will be assessed. (here is contact information: https://www.borger.dk/familie-og-boern/Barsel-oversigt/Barsel-kontakt).
The requirements for being eligible for barselsdagpenge, if you are wage-earner:
1. You must be employed on the first day of your leave or the day before.
2. You must have at least 160 hours within the last four full months before the leave.
3. You must have at least 40 hours a month for at least three of the four months.
If you are a member of an A-kasse: you must have been member for at least 1 year, have earned/have had an income of at least DKK 233,376 (in 2019) during the last 3 years (in total), and must be able to meet the residence requirement, that came into force from January 1, 2019. Only income obtained during A-kasse membership periods can be included.
The requirements for being eligible for barselsdagpenge, if you are self-employed:
1. You have worked for at least 6 months within the last 12 months.
2. You've been working the last month before going on maternity leave.
3. There is a profit in your business. Udbetaling Denmark calculates barselsdagpenge for self-employed persons on the basis of your income, and you will therefore not receive barselsdagpenge if the income is negative. If in the last annual accounts the self-employed had a profit of at least DKK 226,460, then he/she can get the highest possible amount in barselsdagpenge, which is DKK 4,355 per week before tax (rate as of January 1, 2019). If you only have a small or negative income in your business, then you can benefit from a self-employment sickness insurance ("sygedagpengeforsikring"), which is also paid during maternity leave. Read more about sygedagpengeforsikring here (in danish only): https://indberet.virk.dk/sygedagpengeforsikring/selvstaendige/barsel.
4. You have worked at least half the time (18.5 hours a week) in your company.
If you are newly started and have worked as a self-employed for less than 6 months, you can also include periods where you have worked as an employee.
If you meet the requirements as either wage-earner or self-employed, then you do not need to have been member of an A-kasse prior to your maternity leave.
If you are considered wage-earner, and are in doubt whether you will be able to meet the above mentioned requirements as wage-earner, then it will be a good idea to join an A-kasse at least 1 year before you plan to go on maternity leave. In this way you will have more options/more security for being able to get barselsdagpenge. And off course A-kasse membership at the same time insures you against unemployment.
Let me know if you have further questions.
Anders Weber, www.a-kasser.dk